DESC:TECHNICAL FIELD
[1] The present disclosure relates generally to field of alloying of materials. In particular, the present disclosure relates to copper-based alloys for simultaneous high strength and high thermal conductivity applications at room and elevated temperatures.

BACKGROUND
[2] The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[3] Technological demands in recent time have led to a renewed interest in copper-based alloys. Cu and Cu-based alloys have good thermal and electrical conductivity properties, making them excellent material for high heat flux applications. The liner of main combustion chamber in reusable launch vehicles and heat exchangers are made up of Cu-based alloys. Materials for high heat flux application require good high temperature mechanical properties, good thermal conductivity with good oxidation and corrosion resistance at elevated temperature, and Cu is known for having good oxidation and corrosion resistance (see, Metals Handbook, Desk edition, ASM, OH, (1984) Volume 7).Since there is always a trade-off between strength and conductivity, it is difficult to achieve good high temperature strength and thermal conductivity simultaneously.
[4] Apart from high heat flux applications, high strength Cu-based alloys also have long term applications such as heat exchangers and structural applications suitable for marine as well as several other strategic applications. These applications for Cu-based alloys demand for high strength, good thermal conductivity, good creep properties, better corrosion resistance and ease of fabrication.Other applications of Cu-based alloys include non-sparking tools, landing gears, lead frame, electrical contacts, where electrical conductivity is an important factor along with strength (See, K. Ishida, “Copper alloy and process for producing copper alloy”, US20130333812A1, 2013; and S. Nagarjuna et al., “Age hardening studies in a Cu–4.5Ti–0.5Co alloy”, Mater. Sci. Eng. A. 313 (2001) 251–260. doi:10.1016/S0921-5093(00)01834-7).
[5] Over the past few decades, many conventional routes, such as solid solution strengthening, cold working, grain refinement, and dispersion and precipitation hardening, and recently unconventional route like introduction of coherent nano twins have been used to achieve the best combination of strength and conductivity. Strengthening by solid solution doesn’t serve the purpose because the solutes in Cu decreases the conductivity to a larger extent (see, J R Davis, ASM Specialty Handbook Copper and Copper Alloys, ASM International, Materials Park, OH, (2001), volume 3). Cold working of the alloy doesn’t do any good to the conductivity either. Grain refinement increases the grain boundary which further reduces the conductivity. Therefore, all these methods have not been extensively utilized to develop Cu-based alloy possessing high conductivity and good mechanical properties at higher temperature. Development of Cu-based alloys through dispersion and precipitation hardening is one of the possibilities. There were efforts to incorporate dispersions of borides, oxides, carbides and silicidesto form metal matrix composites through powder metallurgy routes (See, D.M. Aylor, “Development of copper-base metal matrix composites materials”, DTNSRDC/SME-85/10, David Taylor Naval Ship R&D Centre (1985); and S.Y. Chang, S.J. Lin, “Fabrication of SiCw reinforced copper matrix composite by electroless copper plating”, Scr. Mater. 35 (1996) 225–231, doi:10.1016/1359-6462(96)00108-X). GLIDCOP AL-15 alloy contains dispersions of Al2O3 in Cu matrix and is one of the famous dispersions strengthened Cu-based alloys. It is reported by Dalder et al. that GLIDCOP AL-15 is thermally the most stable amongst all dispersion hardened alloys (See, N.C. Dalder, W. Ludemann, and B. Schumacher, “Thermal Stability of Four High-Strength, High-Conductivity Copper Sheet Alloys”, UCRL- 88919, and ASM Õ s Copper and Copper Alloys Conf., 1983, material also appears in UCRL-89034-Rev. 1, Conf-830466-Rev-1, DE83 013312 Accession No. 84N10288, DOE Workshop on Copper Alloys, 1983). Since the dispersions of Al2O3, borides (TiB2), carbides and silicides are insulators, they adversely affect the conductivity of the alloy. Further, GLIDCOP AL-15 also shows poor ductility at temperature more than 650°C (See, A. Wycliffe, “Literature Search on High Conductivity Copper Based Alloys,”Final Report IDWA No. 6458-2, Rockwell International Sci. Centre, R5739TC/sn, 1984).
[6] Most of the currently developed high strength high conductivity Cu-based alloys are based on incorporating fine scale intermetallic dispersions and precipitates in the copper matrix. The most prominent among them are GRCop-84 and GRCop-42(See, D.L. Ellis, “GRCop-84: A High-Temperature Copper Alloy for High-Heat-Flux Applications”, http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050123582.pdf; and D.L. Ellis et al., “Thermophysical Properties of GRCop-84”, 2000.http://ntrs.nasa.gov/search.jsp?R=20000064095). GRCop-84 and GRCop-42 are a series of alloys developed by Glen Research Centre, NASA for its Earth-to-orbit program during the 1980s. These alloys have good mechanical properties and high thermal conductivity at room temperature. The creep resistance and oxidation resistance are also good at high temperatures. They draw their high temperature properties through dispersions of Cr2Nbparticles in Cu matrix. Cr2Nb precipitates form congruently during rapid solidification process namely either conventional gas atomization or chill block casting. Consolidation of the powder formed through gas atomization is achieved either through direct extrusion or hot isostatic pressing (HIP). Since the processing of these alloys is mostly through compaction route, a significant cooling rate is necessary to develop the desired microstructure. GRCop-84 alloy shows poor strength at elevated temperature. The oxidation resistance of these alloys is good up to 650 °C due to the formation of protective chromium-niobium oxides. But at temperatures above 650 °C, the oxidation resistance degrades and becomes almost similar to that of Pure Cu.
[7] Precipitation hardening is an effective way to strengthen the Cu matrix. In precipitation hardening, the alloying element forms solid solution with the elements at higher temperature and precipitate on cooling yielding precipitates that are either coherent or semi coherent with the matrix. The strain field associated with these precipitates hinders dislocation motion and results in hardening of the alloy. Many successful alloying additions which promote precipitation hardening in Cu alloys are reported in the literature and some of them have found their ways into commercial product. The most prominent of these alloying additions are Mg and Ti (See, K. Maki, Y. Ito, H. Matsunaga, H. Mori, Solid-solution copper alloys with high strength and high electrical conductivity, Scr. Mater. 68 (2013) 777–780. doi:10.1016/j.scriptamat.2012.12.027.; D.E. Laughlin, J.W. Cahn, The crystal structure of the metastable precipitate in copper-based copper-titanium alloys, Scr. Metall. 8 (1974) 75–78. doi:10.1016/0036-9748(74)90444-X.; and D.E. Laughlin, J.W. Cahn, Spinodal decomposition in age hardening copper-titanium alloys, Acta Metall. 23 (1975) 329–339. doi:10.1016/0001-6160(75)90125-X.). Age hardened Cu-Zr alloy, AMZIRC (Cu-0.15wt.%Zr), and modified alloys with Cr addition to Cu-Zr alloys in various proportions also show good combination of strength and conductivity at relatively lower temperatures (See, N.C. Dalder et al., Thermal Stability of Four High-Strength, High-Conductivity Copper Sheet Alloys , UCRL- 88919, and ASM Õ s Copper and Copper Alloys Conf., 1983, material also appears in UCRL-89034-Rev. 1, Conf-830466-Rev-1, DE83 013312 Accession No. 84N10288, DOE Workshop on Copper Alloys, 1983.; A. Wycliffe, ‘“Literature Search on High Conductivity Copper Based Alloys,”’ Final Report IDWA No. 6458-2, Rockwell International Sci. Centre, R5739TC/sn, 1984.; and D.D. Horn and H.F. Lewis, ‘“Property Investigation of Copper Base Alloys at Ambient and Elevated Temperatures,”’ AEDC-TR-65-72, 1965, (Defence Document Centre No. 467015), p 4, 11, 12, 35, 3.). Cu-1Cr-0.1Zr (C18150) alloy shows improvement in properties compared to AMZIRC (Cu-0.15wt.%Zr). High temperature mechanical strength is, however, not attractive and therefore, limits its application. AMZIRC alloy also exhibits a sharp drop in strength after exposure at temperature above 500 °C.
[8] Another alloy, strengthened through precipitation hardening, NARloy-Z (Cu-3wt.% Ag-0.5 wt.% Zr) is a state-of-the-art alloy and used in liner of main combustion chamber (MMC) of reusable launch vehicle. Ag in Cuused as a hardener through precipitation hardening, whereas Zr is used as a grain refiner. Since this alloy is not commercially used, only a limited database is available. Of the limited information available for NARloy-Z, it offers good thermal properties till the operating temperature of 600 ?C. However, the mechanical properties at room temperature are poor and decreases to below 100 MPa at temperature 500?C and above (see, H.C. de Groh, D.L. Ellis, W.S. Loewenthal, Comparison of GRCop-84 to Other Cu Alloys with High Thermal Conductivities, J. Mater. Eng. Perform. 17 (2008) 594–606. doi:10.1007/s11665-007-9175-3.).
[9] Recently, strengthening of Cu by Ni3Al ordered precipitates is shown by Ishida et al (see, K. Ishida et al., Copper alloy and process for producing copper alloy, US20130333812A1, 2013). Various alloying elements, which include small amount of Si, Ti, Sn, Cr, Fe and Co, have been made to further develop the alloys. Such a development of use of ordered precipitates is generally inspired by the development of Ni-based super-alloys, where Ni3Al ordered precipitates strengthen the matrix.
[10] The design of Ni3Al precipitates in Cu matrix is on the basis of existence of phase field of Cu solid solution and Ni3Al ordered phase having L12 structure that co-exists in Cu-Ni-Al phase diagram (see, Alloy Phase Diagram, ASM, H Baker, 1992). Since Ni and Al form solid solution in Cu, these alloys are expected to have poorer electrical and thermal conductivity. The effects of separate addition of Ni and Al on thermal conductivity and electrical resistivity of pure Cu have been reported (see, C.Y. Ho et al., “Electrical Resistivity of Ten Selected Binary Alloy Systems”, J. Phys. Chem. Ref. Data. 12 (1983) 183–322. doi:10.1063/1.555684.; and C.Y. Ho et al., “Thermal conductivity of ten selected binary alloy systems”, J. Phys. Chem. Ref. Data. 7 (1978) 959–1178. doi:10.1063/1.555583). The increasing content of Ni and Al in Cu solid solution leads to a rapid decrease in the thermal and electrical conductivity values and their simultaneous addition would further degrade the conductivity values. The interesting fact to note is that the effect of Ni addition is more deleterious to conductivity values as Ni addition (?11 at.%) decreases the conductivity values more than the same content of Al addition (?11 at.%) does. So, for a further developments of high conductivity Cu-based alloys without compromising the strength, it is essential that the solute elements such as Ni are limited in the Cu matrix. Furthermore, the high temperature properties of these alloys have also been not reported in the patent publication by Ishida et al.
[11] The recent development of GRcop-84 alloys, which is currently second to none, is based on utilizing very limited or almost no solubility of Cr or Nb in Cu matrix. The immiscibility of solute elements promotes good conductivity, while strengthening is affected by intermediate Cr2Nb particles. However, processing of this alloy is carried outby powder metallurgy route.
[12] There is, therefore, a requirement in the art for an alloy that can overcome the limitations faced by the copper alloys known in the art, as mentioned above.
[13] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[14] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability.

OBJECTS
[15] It is an object of the present disclosure to provide a new class of Cu-based alloys that obviates one or more problems due to limitations and disadvantages of the related art.
[16] It is another object of the present disclosure to provide a Cu-based alloy that exhibits both high strength and high conductivity at operating temperatures.
[17] It is another object of the present disclosure to provide a new class of Cu-based alloy that exhibits outstanding mechanical strength and excellent thermal properties, especially at high temperatures.
[18] It is another object of the present disclosure to provide a new class of Cu-based alloy that has various favourable properties such as, resistance to degradation under harsh environmental conditions, high strength, excellent thermal and electrical conductivity, resistance to corrosion, good creep properties and ease of fabrication.
[19] It is yet another object of the present disclosure to provide a new class of Cu-based alloy that can be used in a wide variety of applications, including high heat flux applications.

SUMMARY
[20] The present disclosure relates generally to field of alloying of materials. In particular, the present disclosure relates to copper-based alloys for simultaneous high strength and high thermal conductivity applications at room and elevated temperatures.
[21] In an aspect, the present disclosure provides a copper (Cu) alloy. The copper (Cu) alloy includes:at least a fraction of a first material selected from a group of materials comprising cobalt (Co) and iron (Fe); at least a fraction of a second material selected respectively from another group of materials comprising aluminium (Al) and silicon (Si); anda remaining fraction of copper (Cu) along with incidental impurities.
[22] In another aspect, the copper (Cu) alloy comprises L12ordered precipitates of A3B type of ordering of the first material and the respective second material in a copper (Cu) matrix to provide the copper (Cu) alloy with improved mechanical properties and thermal properties.
[23] In another aspect, formation of L12 ordered precipitates of the first material and the respective second material occurs on a first heat treatment and a subsequent second heat treatment of the copper (Cu) alloy.
[24] In another embodiment, the fraction of the first material (A) is in the range of 1 to 6 atomic %.
[25] In an embodiment, the fraction of the second material (B) is in the range of 1 to 12 atomic %.
[26] In another embodiment, fraction of copper (Cu) remaining in the alloy, along with incidental impurities is in the range of 82 to 92 atomic %.
[27] In another embodiment, the first heat treatment of the copper (Cu) alloy is at a temperature range of 990 °C and 1020 °C and for a duration of more than 4 hours.
[28] In another embodiment, the second heat treatment of the copper (Cu) alloy is at a temperature range of 450 °C and 550 °C and for a duration of up to 2 to 20 hours.
[29] In another embodiment, the first heat treatment and the second heat treatment are conducted in a vacuum of more than 10-5 mbar.
[30] In another embodiment, the hardness value of the copper (Cu) alloy is in the range of 110 to 220 HV.
[31] In another embodiment, mechanical strength of the copper (Cu) alloy is in the range of 350 to 600 MPa, 300 to 350 MPa and 100 to 250 MPa at room temperature, 400 °C and 600 °C respectively.
[32] In another embodiment, thermal conductivity of the copper (Cu) alloy is in the range of 130 to 245 W/mK, 180 to 300 W/mK and 200 to 340 W/mK at room temperature, 400 °C and 600 °C respectively.
[33] In another embodiment, the alloy comprises a second ordered precipitate of AB type of orderingof the first material and the second material in the copper (Cu) matrix.
[34] In another embodiment, the alloy comprises at least a fraction of a third material selected from tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), chromium (Cr), zirconium (Zr), germanium (Ge) and a combination thereof.
[35] In an aspect, the present disclosure provides a method for preparing a copper (Cu) alloy. In another aspect, at least a fraction of a first material and at least a fraction of a second material are alloyed with a remaining fraction of copper (Cu) and incidental impurities, said first material selected from a group of materials comprising cobalt (Co) and iron (Fe) and said second material selected respectively from another group of materials comprising aluminium (Al) and silicon (Si).
[36] In another aspect, the copper (Cu) alloy is maintained at a first temperature for a first duration of time to enable dissolution of the first material and the second material is a copper (Cu) matrix.
[37] In another aspect, the copper (Cu) alloy is maintained at a second temperature for a second duration of time.
[38] In another aspect, formation of L12 ordered precipitates of A3B type of ordering of the first material and the second material in a copper (Cu) matrix provides the copper (Cu) alloy with improved mechanical properties and thermal properties.
[39] In an embodiment, the fraction of the first material (A) is in the range of 1 to 6 atomic %.
[40] In another embodiment, the fraction of the second material (B) is in the range of 1 to 12 atomic %.
[41] In another embodiment, fraction of copper (Cu) remaining in the alloy, along with incidental impurities is in the range of 82 to 92 atomic %.
[42] In another embodiment, the first temperature and the first duration are, respectively, in the range of 990 °C and 1020 °C and 4 hours and more.
[43] In another embodiment, the second temperature and the second duration are, respectively, in the range of 450 °C and 550 °C and up to 2 to 20 hours.
[44] In another embodiment, the first temperature and the second temperature are maintained at respectively the first duration and the second duration at a vacuum of more than 10-5 mbar.
[45] In another embodiment, a second ordered precipitate of AB type of ordering of the first material and the second material is formed in the copper (Cu) matrix.
[46] In another embodiment, at least a fraction of a third material is alloyed with the copper (Cu), the third material selected from tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), chromium (Cr), zirconium (Zr), germanium (Ge) and a combination thereof.
[47] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments.

BRIEF DESCRIPTION OF DRAWINGS
[48] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure, and wherein:
[49] FIG. 1 is a flow chart showing an exemplary method for preparing copper-based alloys in accordance with one embodiment of the present disclosure.
[50] FIG. 2A and FIG. 2B show optical micrograph and elemental mapping of Cu-5Co-10Al alloy after solution treatment, respectively.
[51] FIG. 3A is Vickers Hardness values for the Cu-5Co-10Al alloy, aged at 500?C for different aging time.
[52] FIG. 3B shows aging response in terms of Hardness value for Cu-2.5Fe-2.5Si and Cu-1.0Fe-1.0Si alloys at aging temperature of 450?C. Hardness values measured using 200 gf load for 10 seconds indentation time.
[53] FIG. 4A shows TEM dark-field image of aged Cu-5Co-10Al alloy from (100) superlattice spot in the [001] zone axis.
[54] FIGs. 4B and 4C show SAD Patterns from the [001] and [110] zone axes.
[55] FIG. 4D shows [112] SAD pattern of aged Cu-2.5Fe-2.5Si alloy.
[56] FIGs. 4E and 4G show complimentary bright field and dark field images taken in two beam condition.
[57] FIG. 4F shows precipitate size distribution of Cu-2.5Fe-2.5Si alloy.
[58] FIGs. 5A and 5B show HAADF-STEM images along with energy dispersive spectroscopy (EDS) elemental mapping of the precipitates using a STEM nano probe of Cu-5Co-10Al alloy and Cu-2.5Fe-2.5Si alloy, respectively.
[59] FIG. 6A is a graph showing comparison of density of invented Cu-5Co-10Al alloy with other commercially used alloys.
[60] FIG. 6B is a graph showing compressive specific yield strength of Cu-5Co-10Al alloy at different temperatures, and its comparison with GRCop-84 alloy.
[61] FIG. 7A shows tensile stress versus strain (%) plots of Cu-5Co-10Al alloy at room temperature and 600°C.
[62] FIG. 7B is tensile stress versus strain (%) plots at room temperature, 400 °C and 600 °C for Cu-2.5Fe-2.5Si alloy.
[63] FIG. 8 is a graph showing comparison of yield strength of alloys of the present disclosure with other available Cu-based alloys.
[64] FIG. 9 is comparison of ultimate tensile strength of alloys of the present disclosure with different Cu-based alloys.
[65] FIG. 10A is a graph showing effect of Ni and Al addition on thermal conductivity of pure Cu, in accordance with embodiments of the present disclosure.
[66] FIG. 10B is a graph showing effect of Ni and Al addition on electrical resistivity of pure Cu, in accordance with embodiments of the present disclosure.
[67] FIG. 10C shows thermal conductivity of Cu-5Co-10Al, Cu-2.5Fe-2.5Si, Cu-1.0Fe-1.0Si alloys and pure Cu at different temperatures, in accordance with embodiments of the present disclosure.
[68] FIGs. 11A and 11B show comparison of thermal conductivity values with yield strength of Cu-5Co-10Al, Cu-2.5Fe-2.5Si and Cu-1.0Fe-1.0Si alloys with other state of the Cu-based alloys at room temperature and 600 °C, respectively.
[69] FIG. 12A is a plot comparing the electrical resistivity of alloys of the present disclosure with pure copper.
[70] FIG. 12B is a plot in which the electrical conductivity of the invented Cu-5Co-10Al, Cu-2.5Fe-2.5Si and Cu-1.0Fe-1.0Si alloys is presented as % of electrical conductivity of pure copper.

DETAILED DESCRIPTION
[71] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[72] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[73] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[74] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. These exemplary embodiments are provided only for illustrative purposes and so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. The invention disclosed may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Various modifications will be readily apparent to persons skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention.
[75] The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non – claimed element essential to the practice of the invention.
[76] The following discussion provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[77] Embodiments of the present disclosure provide new class of copper (Cu) based alloys where Cu matrix is strengthened by coherent L12 precipitates of A3B type where, A represents Fe or Co and B represents Si or Al.The disclosed copper-base alloys are primarily strengthened by uniform distribution of coherent L12 ordered precipitates in Cu matrix. The precipitates are of nano-sized (size ranges from 4-12 nm) and near spherical in shape. The copper-basedalloys disclosed herein can exhibit both high strength and high conductivity,particularly at high temperatures.The copper-based alloys of the present disclosure are formulated to exhibit an array of outstanding properties including high mechanical strength, excellent thermal and electrical conductivity, resistance to degradation under harsh environmental conditions, oxidation and corrosion resistance, high temperature creep resistance, ease of fabrication, among others. The copper-based alloys described herein find use in a wide variety of application, including high heat flux applications.
[78] In one aspect, the present disclosure is directed to copper-cobalt-aluminium (Cu-Co-Al) alloy having high strength and high conductivity characteristics.According to embodiments of the present disclosure, the Cu-Co-Al alloy can have the following chemical composition, in atomic percentages: from 10 to 12% aluminium, from 4.5 to 6% cobalt, and copper as the balance to 100%.
[79] According to embodiments, the disclosed Cu-Co-Al alloy can include the specified elements in the following proportions by weight: from 4.5 to 5.5 % aluminium, from 4.5 to 6.0 % cobalt, with the balance to total 100% being copper and unavoidable impurities. The alloy composition, when subjected to metallurgical heat treatment of solutionising and aging, yields a microstructure that contains uniform distribution of spherical Co3Al (L12 ordered) precipitates in Cu matrix.
[80] In one exemplary embodiment, the Cu-Co-Al alloy can be prepared by arc melting a mixture of elemental aluminium, cobalt and copper in defined amounts to form analloy, followed by subjecting the alloy to solution treatment by keeping the alloy at 990 to 1020 ºC for 4 hours or more to obtain a single phase solid solution of Cu containing Co and Al. The solution treatment results in dissolution of Co and Al in Cu matrix. The solution treated alloy may subsequently be aged by keeping at 450 ?C to 550 ?C for 2 to 20 hours that enables precipitates to come out of the Cu matrix.
[81] According to embodiments of the present disclosure, the Cu-Co-Al alloy, after solutionising at temperature ranging from 990?C to 1020?C and aging treatment at temperature ranging from 450?C to 550?C, can yield coherent ordered precipitates of L12 crystal structure of Co3Al composition in fcc Cu matrix. Further, the Cu-Co-Al alloy, after maintaining at holding temperature for a predetermined period of time, can yield a second ordered precipitate of B2 ordered structure of CoAl composition having rod morphology that coexist with previously precipitated L12 ordered phase.
[82] In one particular embodiment, the precipitation strengthened Cu-Co-Al alloy can exhibit a minimum strength in the range of 350 to 400 MPa, 300 to 350 MPa and 200 to 250 MPa at room temperature, 400 ?C and 600 ?C, respectively.
[83] In another particular embodiment, the Cu-Co-Al alloy can exhibit minimum thermal conductivity in the range of 130 to 145 W/mK, 180 to 210 W/mK and 200 to 225 W/mK at room temperature, 400 ?C and 600 ?C, respectively.
[84] In another particular embodiment, the Cu-Co-Al alloy can exhibit low weight gains when exposed to oxidizing environments. In one exemplary embodiment, oxidation weight gain of theCu-Co-Al alloy can be less than 1 mg/cm2, after exposure to static air at the temperature of 600 ?C and 700 ?C for 1000 minutes.
[85] In another particular embodiment, the Cu-Co-Al alloy exhibits good electrical conductivity, particularly, at high temperature (33% of IACS at 400 ?C).
[86] In some embodiments, the Cu-Co-Al alloy disclosed herein can further include additional alloying element to improve structural integrity of the alloy. The additional element is preferably one or more of the following elements: Mo, W, Ta and Nb. Said additional elements can present individually in an amount of 0.1 to 0.25 atomic %.A part of the additionally added elements may partition the Co3Al precipitates and make them hard and stable, and the remaining part thereof may remain in fcc Copper matrix (trapped during solutionising) to provide solid solution strengthening.
[87] In some other embodiments, minor proportions of Cr and Zr may also be added to the Cu-Co-Al alloy to further strengthen the alloy. Preferably, Cr and Zr may be added up to 1.0 atomic % and 0.1 atomic % respectively.The Cr addition leads to precipitation of Cr in parent Cu matrix and thus provides additional strength. Moreover, Cr addition also helps in improving oxidation and corrosive properties at high temperature. Zr addition also leads to precipitation of Zr precipitates in Cu matrix and again provides additional strength.In some embodiments, the Cu-Co-Al alloy can further include 1 to 2 atomic % vanadium (V) and 2 to 4 atomic % Co. Co and V addition can form L12 ordered Co3V precipitate in the fcc copper matrix.
[88] In another aspect, the present disclosure is directed to copper-iron-silicon (Cu-Fe-Si) alloy having high strength and high conductivity characteristics. According to embodiments of the present disclosure, the Cu-Fe-Si alloy can have the following chemical composition, in atomic percentages: from 1 to 2.5% iron, from 1 to 2.5% silicon, and copper as the balance to 100%.The Cu-Fe-Si alloy can include the specified elements in the following proportions by weight: from 0.9 to 2.3% iron, from 0.5 to 1.2% silicon, with the balance to total 100% being copper and unavoidable impurities.The Cu-Fe-Si alloy is strengthened during thermal processing by uniform dispersion of Fe3Si (L12 ordered) precipitates in copper matrix. Both Fe and Si partition from copper matrix to form coherent ordered L12 precipitates in the copper matrix.
[89] In various embodiments, the precipitation strengthened Cu-Fe-Si alloy can be prepared by the same method as described above for Cu-Co-Al alloy.The Cu-Fe-Si alloy derives its strength primarily from the presence of uniformly distributed nano sized Fe3Si precipitates having L12 structure. The Fe3Si precipitates are coherent with the Cu matrix. The coherency strain associated with the precipitates and the ordering restricts the motion of dislocation and thus imparts strength to the Cu-Fe-Si alloy. Thermal and electrical conductivities of Cu-Fe-Si alloy are comparable and even better than some of the commercially available Cu alloys.
[90] In various embodiments, the disclosed Cu-Fe-Si alloy, solutionized at temperature ranging from 990?C to 1020?C for 4 hours or more and aged in the temperature range of 450?C to 550?C for 2 to 20 hours, can yield coherent precipitates of ordered intermetallic of Fe and Si having L12 structure (Fe3Si).
[91] In some embodiments, elemental Al may be added to the Cu-Fe-Si alloy in minor proportion to further improve performance of the alloy. The composition range can be Fe-1.0 to 5.0 at. %, Al-0 to 12 at. % and Si-0.5 to 2.5 at. % and rest being Cu. Thermal processing of the alloy provides a second kind of precipitates in addition to Fe3Si.Some amount of Al goes into the copper matrix and thus provides solid solution strengthening to the matrix. Moreover, Al addition also helps in improving the oxidation properties at elevated temperature through formation of protective ?-Al2O3.
[92] In some embodiments, the disclosed Cu-Fe-Si alloy may have intermetallic FeSi coexisting with Fe3Si.
[93] In one particular embodiment, the precipitation strengthened Cu-Fe-Si alloy disclosed herein can exhibit a minimum strength in the range of 550 to 600 MPa, 300 to 350 MPa and 100 to 140 MPa at room temperature, 400 ?C and 600 ?C, respectively.
[94] In another particular embodiment, the Cu-Fe-Si alloy disclosed herein can exhibit minimum thermal conductivity in the range of 230 to 245 W/mK, 280 to 300 W/mK and 300 to 340 W/mK at room temperature, 400 ?C and 600 ?C, respectively.
[95] In some embodiments, the Cu-Fe-Si alloy disclosed herein can further include one or more additional elements selected from Ge, Al, Nb and Ta. Said additional elements can present individually in an amount of 0.1 to 5 atomic %.
[96] In yet another aspect, the present disclosure is directed to industrial articles made of the precipitation hardened copper-based alloys of the present disclosure.
[97] While the foregoing description discloses various embodiments of the disclosure, other and further embodiments of the invention may be devised without departing from the basic scope of the disclosure. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
[98] The present disclosure is further explained in the form of following examples. However, it is to be understood that the foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.
[99] The Cu-Co-Al alloy containing Al in the range of 10 to 12 atomic %, Co in the range of 4.5 to 6 atomic % with rest being copper, was prepared by the method as shown in the flowchart in FIG. 1.The alloywasmelted under an atmosphere of argon gas. The melted alloy was cast in the form of rods and slabs in water cooled split copper mould. The cast alloy shows dendritic structure with segregation at micron scale. To produce homogeneous supersaturated solid solution of Co and Al in Cu from the cast alloy, the alloywas solution treated under vacuum (10-5 mbar, to avoid oxidation) at 990 to 1020 ºC for 4 hours or more. FIG. 2A shows one of the typical examples of solutionized microstructure of Cu-5at. %Co-10at. %Al alloy (hereafter mentioned as Cu-5Co-10Al) and the elemental mapping in FIG. 2B confirms a uniform distribution of Al and Co in Cu matrix in solution treated alloy. To develop the age-hardenable copper alloys for high temperature application, the single-phase solid solution was further aged under vacuum at 450 to 550 ?C for different durations. The embodiments report alloys that are aged for 10 hours at 500 ºC and water quenched. The hardness of the alloy was measured at a load of 200 gf for a dwell time of 10 seconds. The hardness values of one such alloy (Cu-5Co-10Al) is given in FIG. 3A. The hardness values of the Cu-5Co-10Alalloy are in the range of 160 to 220 HV. The hardness plots for Cu-2.5 at.%Fe-2.5 at.% Si (hereafter named as Cu-2.5Fe-2.5Si) and Cu-1.0 at.%, Fe-1.0 at.%, Si (hereafter named as Cu-1.0Fe-1.0Si) alloys (given the solution treatment similar to Cu-Co-Alalloy followed by aging) with time at the aging temperature of 450 ?C are plotted in FIG. 3B. The hardness values for Cu-2.5Fe-2.5Si alloy are between 130 to 136 HV.
[100] Transmission electron microscope (TEM)is used for microstructural analysis. As can be seen from FIGs. 4B and 4C, the SADP’s of 10 hours aged Cu-5Co-10Al alloy show the presence of L12 structure precipitates inside copper matrix. The precipitates are coherent with the matrix. Dark-field image taken from (100) superlattice spot in the [001] zone axis is shown in FIG. 4A. The qualitative mapping of the precipitates was carried out in TEM.FIG. 5A shows elemental mapping in nano probe STEM mode using HAADF detector of Cu-5Co-10Al alloy (aged at 500 °C for 10 hours). As can be seen from FIG. 5A, the EDS elemental maps using a STEM nanoprobe show partitioning of Co and Al in the precipitate, whereas no partitioning of Cu in precipitate is detected. The size of the precipitate is calculated to be 8.0 nm ± 2.0 nm.
[101] The Cu-Fe-Si alloy containing Fe in the range of 1 to 2.5%, Si in the range of 1 to 2.5% with rest being copper, was prepared by the method as shown in the flowchart in FIG. 1.The bright field image and its counterpart dark field image of 450 ?C for 10 h aged Cu-2.5Fe-2.5Si alloy are presented in FIGs. 4E and 4G. FIG. 4D shows [211] SAD pattern of Cu-2.5Fe-2.5Si alloy. FIG. 4F shows precipitate size distribution of Cu-2.5Fe-2.5Si alloy. The superlattice reflections present in the selected area diffraction pattern along the [211] zone axis pattern confirms the precipitates to have L12 ordering. The elemental mapping, as shown in FIG. 5B, in STEM nano probe mode shows that Si partitions more to Fe than Cu. As a result, the inventors could obtain a new type of ordered L12 precipitate of Fe3Si composition in the Cu matrix.
[102] High temperature mechanical properties (compression test results at 10-3s-1strain rate) of Cu-5Co-10Al alloy are presented in Table-1. The invented Cu-5Co-10Al alloy shows good mechanical reliability even at temperature above 600 ?C. The density of invented alloy (Cu-5Co-10Al) along with data forother available alloys is presented as bar plot in FIG. 6A. The Cu-5Co-10Al alloy is lighter than other alloys. FIG. 6B shows the comparison of specific yield strength of Cu-5Co-10Al alloy with GRCop-84 to highlight the role of the density that plays a crucial role in governing the overall weight and thus increasing the efficiency. The Cu-5Co-10Al alloy is lighter than GRCop-84 and having densities in the range of 8.10 to 8.20 gm/cm3. The specific yield strength comparison values for Cu-5Co-10Al alloy is greater than GRCop-84 at all temperature, and at 800 ºC it becomes almost 4 times of GRCop-84. Thus, the developed alloy can be a potential candidate for heat flux application, as far as mechanical strength at temperature greater than 600 °C is concerned.
Table-1
Test Temperature Compressive Yield Strength (MPa) Specific Compressive Yield Strength (KNm/Kg) of Cu-5Co-10Al
25 °C 380 46.3
400 °C 323 39.3
600 °C 248 30.2
700 °C 147 17.9
800 °C 91 11.1

[103] The materials for high temperature applications demand good plasticity at both room and service temperature to avoid sudden failure of the components. The tensile test results of Cu-5Co-10Al alloy are shown in FIG. 7A. The tensile test shows the room temperature yield strength of 350 ± 25 MPa and UTS of 580 ± 40 MPa with ductility of more than 35%. The yield strength and UTS at 600 ºC is 225 ± 20 MPa and 255±20 MPa, respectively, which is greater than any other developed Cu-based alloys for high heat flux application. Engineering Stress vs. strain plots tested under tension at room temperature and at different high temperatures (400°C and 600°C) for Cu-2.5Fe-2.5Si are shown in FIG. 7B. The Cu-2.5Fe-2.5Si alloy shows the 0.2% proof stress of 470 MPa to 600 MPa at room temperature. These alloys exhibit higher yield strength at room temperature as compared to other available commercial and competitive Cu-based alloys. High temperature tensile test data further indicate that these alloys can retain their considerable amount yield strength both at 400 °C (300 MPa to 350 MPa) and at 600°C (100 MPa to 140 MPa) which are also quite good as compared to other commercially available Cu-based alloys.
[104] Comparison of yield strength (in compression) and ultimate yield strength (in tension)with other commercially used Cu-based alloys for high heat flux application is shown in FIG. 8 and FIG. 9, respectively and listed in Table-2 (along with their compositions). The comparison shows comparable room temperature strength of Cu-5Co-10Al with other alloys, but superior high temperature strength (600 ºC) than other commercially used high heat flux Cu-based alloy. Present results have established that the invented alloys exhibit an excellent mechanical strength both at room temperature and at elevated temperatures.
Table-2

Alloys Yield strength (MPa)
Room Temperature 400 °C 600 °C
GRCop-84
(Cu-8 at. %Cr-4 at. %Nb) 310 150 80
AMZIRC (C15000)
(Cu-0.1 at. % Zr) 460 350 100
NARloy-Z (Cu- 1.79 at. % Ag- 0.35 at. % Zr) 145 70 45
GlidCop Al-15 (Cu-0.35 at. %Al- 0.67 at. % O) 435 220 135
CuCrZr (Cu- 1.22 at. % Cr- 0.07 at. % Zr) 500 350 150
Cu-5Co-10Al (Cu- 5 at. % Co- 10 at. % Al) 380 323 248
Cu-2.5Fe-2.5Si (Cu- 2.5 at. % Fe- 2.5 at. % Si) 580 320 128
Cu-1.0Fe-1.0Si (Cu- 1.0 at. % Fe- 1.0 at. % Si) 467 128 100

[105] Ability to dissipate heat is an important attribute for high strength high temperature copper-based alloys. We present the temperature dependent thermal properties for both the sets of the alloys invented by us. The thermal properties were evaluated using laser flash method of thermal conductivity measurements. FIG. 10A shows effect of Ni and Al addition on thermal conductivity of pure Cu. FIG. 10B shows effect of Ni and Al addition on electrical resistivity of pure Cu. The variation in thermal conductivity with temperature for Cu-5Co-10Al, Cu-2.5Fe-2.5Si, Cu-1.0Fe-1.0Si and pure Cu is plotted in FIG. 10C. All of the invented alloys show an increase in thermal conductivity with temperature till at least 600 °C. The total thermal conductivity values of Cu-Co-Al alloy(e.g. Cu-5Co-10Al) shows an increase from 130-145 W/mK to 200-225 W/mK with the increase in temperature from 50 °C to 600 °C. Similarly, the Cu-Fe-Si alloy (e.g. Cu-2.5Fe-2.5Si and Cu-1.0Fe-1.0Si) also exhibits excellent thermal conductivity in the range of 230 W/mK to 245 W/mK at room temperature and from 300 W/mK to 340 W/mK at 600 °C.Variation in thermal conductivity with temperature for Cu-5Co-10Al, Cu-2.5Fe-2.5Si, Cu-1.0Fe-1.0Si and GRCop-84 is presentedin Table-3.
Table-3

Alloys Thermal Conductivity
50 °C 100 °C 400 °C 600 °C 700 °C 800 °C
GRCop-84
(Cu-8 at. %Cr-4 at. %Nb) 290 - 306 300 295 290
Cu-5Co-10Al
(Cu- 5 at. % Co- 10 at. % Al) 144 156 204 224 210 185
Cu-2.5Fe-2.5Si
(Cu- 2.5 at. % Fe- 2.5 at. % Si) 235 238 290 313 319 295
Cu-1.0Fe-1.0Si
(Cu- 1.0 at. % Fe- 1.0 at. % Si) 242 251 302 337 335 298

[106] Comparison plots between thermal conductivity and yield strength at room temperature and 600 °C for representative alloys of this invention and other commercially available alloys are given in FIG. 11A and FIG. 11B. Compared to room temperature properties, the invented alloys stand in a better position at 600 °C as compared with other alloys.
[107] Other than having high heat flux application, the present invention also aims at electrical applications of copper-based alloys such as non-sparking tools, landing gears, lead frame, and electrical contacts. All the aforementioned applications demand for good mechanical strength, plasticity and above of all good electrical conductivity. The electric resistivity measurements of present invented alloys were carried out using four probe method of electrical resistivity measurements. Electrical resistivity values of some of the invented alloys and its comparison are presented in FIG. 12A. The values show that the invented alloys can be potential candidates for some of the electrical applications and especially for application at high temperature (=400 °C).
[108] The electrical conductivity values of the invented alloys as % of pure copper is plotted in FIG. 12B. The electrical conductivity values of Cu-5Co-10Al alloy have increased from 18% of pure Cu to 33% of pure Cu with increase in temperature from room temperature to 400 °C. The Cu-Co-Al alloy (e.g. Cu-5Co-10Al) has the electrical conductivity in the range of 15 to 20% of pure Cu at room temperature and 30 to 35% of pure Cu at 400 °C. Whereas, the Cu-Fe-Si alloy (e.g. Cu-2.5Fe-2.5Si and Cu-1.0Fe-1.0Si) has electrical conductivity in the range of 56 to 60% at room temperature and 74 to 78% at 400 °C. Generally, the concentration of solute elements present in the solid solution largely degrades the electrical conductivity.
[109] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive patent matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “includes” and “including” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C ….and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practised with modification within the spirit and scope of the appended claims.
[110] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES
[111] The present disclosure provides a new class of Cu-based alloys that obviates one or more problems due to limitations and disadvantages of the related art.
[112] The present disclosure provides a Cu-based alloy that exhibits both high strength and high conductivity at operating temperatures.
[113] The present disclosure provides a new class of Cu-based alloy that exhibits outstanding mechanical strength and excellent thermal properties, especially at high temperatures.
[114] The present disclosure provides a new class of Cu-based alloy that has various favourable properties such as, resistance to degradation under harsh environmental conditions, high strength, excellent thermal and electrical conductivity, resistance to corrosion, good creep properties and ease of fabrication.
[115] The present disclosure provides a new class of Cu-based alloy that can be used in a wide variety of applications, including high heat flux applications.
,CLAIMS:1. A copper (Cu) alloy comprising:
at least a fraction of a first material (A) selected from a group of materials comprising cobalt (Co) and iron (Fe);
at least a fraction of a second material (B) selected respectively from another group of materials comprising aluminium (Al) and silicon (Si); and
a remaining fraction of copper (Cu) along with incidental impurities,
wherein the copper (Cu) alloy comprises L12 ordered precipitates of A3B type ordering of the first material and the respective second material in a copper (Cu) matrix to provide the copper (Cu) alloy with improved mechanical properties and thermal properties, and
wherein formation of L12 ordered precipitates of the first material and the respective second material occurs aftera first heat treatment and a subsequent second heat treatment of the copper (Cu) alloy.
2. The alloy as claimed in claim 1, wherein the fraction of the first material (A) is in the range of 1 to 6 atomic %.
3. The alloy as claimed in claim 1, wherein the fraction of the second material (B) is in the range of 1 to 12 atomic %.
4. The alloy as claimed in claim 1, wherein fraction of copper (Cu) remaining in the alloy, along with incidental impurities is in the range of 82 to 92 atomic %.
5. The alloy as claimed in claim 1, wherein the first heat treatment of the copper (Cu) alloy is at a temperature range of 990 °C and 1020 °C and for a duration of more than 4 hours.
6. The alloy as claimed in claim 1, wherein the second heat treatment of the copper (Cu) alloy is at a temperature range of 450 °C and 550 °C and for a duration of up to 2 to 20 hours.
7. The alloy as claimed in claim 1, wherein the first heat treatment and the second heat treatment are conducted in a vacuum of more than 10-5 mbar.
8. The alloy as claimed in claim 1, wherein the hardness value of the aged copper (Cu) alloy is in the range of 110 to 220 HV.
9. The alloy as claimed in claim 1, wherein mechanical strength of the copper (Cu) alloy is in the range of 350 to 600 MPa, 300 to 350 MPa and 100 to 250 MPa at room temperature, 400 °C and 600 °C respectively.
10. The alloy as claimed in claim 1, wherein thermal conductivity of the copper (Cu) alloy is in the range of 130 to 245 W/mK, 180 to 300 W/mK and 200 to 340 W/mK at room temperature, 400 °C and 600 °C respectively.
11. The alloy as claimed in claim 1, wherein the alloy comprises a second ordered precipitates AB type of ordering of the first material and the second material in the copper (Cu) matrix.
12. The alloy as claimed in claim 1, wherein the alloy comprises at least a fraction of a third material selected from tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), chromium (Cr), zirconium (Zr), germanium (Ge) and a combination thereof.
13. A method for preparing a copper (Cu) alloy, said method comprising the steps of:
alloying at least a fraction of a first material (A) and at least a fraction of a second material (B) with a remaining fraction of copper (Cu) and incidental impurities, said first material selected from a group of materials comprising cobalt (Co) and iron (Fe) and said second material selected respectively from another group of materials comprising aluminium (Al) and silicon (Si);
maintaining the copper (Cu) alloy at a first temperature for a first duration of time to enable dissolution of the first material and the second material is a copper (Cu) matrix; and
maintaining the copper (Cu) alloy at a second temperature for a second duration of time,
wherein formation of L12 ordered precipitates of A3B type ordering of the first material and the second material in acopper (Cu) matrix provides the copper (Cu) alloy with improved mechanical properties and thermal properties.
14. The method as claimed in claim 12, wherein the fraction of the first material (A) is in the range of 1 to 6 atomic %.
15. The method as claimed in claim 12, wherein the fraction of the second material (B) is in the range of 1 to 12 atomic %.
16. The method as claimed in claim 12, wherein fraction of copper (Cu) remaining in the alloy, along with incidental impurities is in the range of 82 to 92 atomic %.
17. The method as claimed in claim 12, wherein the first temperature and the first duration are, respectively, in the range of 990 °C and 1020 °C and 4 hours and more.
18. The method as claimed in claim 12, wherein the second temperature and the second duration are, respectively, in the range of 450 °C and 550 °C and up to 2 to 20 hours.
19. The method as claimed in claim 12, wherein the first temperature and the second temperature are maintained at respectively the first duration and the second duration at a vacuum of more than 10-5 mbar.
20. The method as claimed in claim 12, wherein a second ordered precipitates of AB type of ordering of the first material and the second material is formed in the copper (Cu) matrix.
21. The method as claimed in claim 12, wherein the at least a fraction of a third material is alloyed with the copper (Cu), the third material selected from tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), chromium (Cr), zirconium (Zr), germanium (Ge) and a combination thereof.