18[0108]The ThermoCalc software (Ni25 database) based onthe CALPHAD method was used tocalculate the volume fraction (volume percent) of equilibrium phase σin superalloys Ex1 to Ex14at 950°C and 1050°C(see Table 5).[0109]The calculated volume fractions of the phaseσare relatively 5small, reflecting a low sensitivity to TCPprecipitation. These results therefore corroborate the results obtained with the New PHACOMP method(parameter M̅d).[0110]Mass concentration of chromium dissolved in the γmatrix[0111]The ThermoCalc software (Ni25 database) based onthe 10CALPHAD method was used tocalculate the chromium content (in percent by mass) in the γphase at equilibrium in superalloys Ex1 to Ex14at 950°C, 1050°C and 1200°C.[0112]As can be seen in Table 5, the chromium concentrations in the γ phase are higher for superalloys Ex1 to Ex10compared withthe 15chromium concentrations in the γ phase for commercial superalloys Ex12 to Ex14,which is conduciveto better corrosion and hot oxidation resistance.[0113]Table 5Volume fraction of TCPtype σ (in%vol)Chromium content in the γphase (in%by mass)950°C1050°C950°C1050°C1200°CEx11.10.58.637.655.79Ex21.40.79.028.036.25Ex31.20.68.637.645.79Ex41.40.78.777.825.96Ex51.20.18.867.816.05Ex60.90.111.009.506.80Ex70.80.68.357.305.45Ex80.90.210.839.637.57Ex91.20.511.259.957.71Ex100.40.010.409.206.80Ex110.7-12.8010.907.84Ex121.20.57.406.434.82Ex130.90.43.623.362.77
19Ex141.00.38.377.105.25[0114]Very high temperature creep property[0115]Creep tests were carried out on the superalloys Ex2, Ex5, Ex6, Ex11, Ex13 and Ex14. Creep tests were performed at 1200°C and 80 MPa according to the NF EN ISO 204 standard of August 2009 (Guide 5U125_J).[0116]The results of creep tests in which the superalloys were loaded (80 MPa) at 1200°C are shown inTable 6. The results represent the time in hours (h) at specimen failure.[0117]Table 610Time to break (hour)Ex241Ex565Ex650Ex1054Ex119Ex1359Ex1413[0118]SuperalloysEx2, Ex5, Ex6 and Ex10 exhibit better creep behaviorthan Ex11 and Ex14 alloys. Superalloy Ex13 also has good creep properties.[0119]Cyclic oxidation property at 1150°C15[0120]The superalloysarethermally cycled as described in INS-TTH-001 and INS-TTH-002: Oxidative Cycling Test Method (Mass Loss Test and Thermal Barrier).[0121]A specimen ofthe superalloy undertest (pin having a diameter of 20 mm and a height of 1mm) is subjected to thermal cycling, each 20cycle of which comprises a rise to 1150°C in less than 15 min (minutes), a60 min stop at 1150°C and turbine-cooling of the specimen for 15 min.[0122]The thermal cycle isrepeated until a loss in mass of the test piece equal to 20 mg/cm² (milligrams per square centimeter) is observed.[0123]The service life ofthe superalloystested is shownin Table 7.25[0124]Table 7
20Service life(hours)Ex21310Ex5> 1700Ex10> 1700Ex11~ 230Ex12~ 480Ex13~ 100[0125]It can be seen that Ex2, Ex5 and Ex10superalloyshave a much longer service life than Ex11, Ex12 and Ex13superalloys. It should benoted that the oxidation properties ofthe Ex13 superalloy are much poorer than those of the Ex2, Ex5 and Ex10superalloys.5[0126]Microstructural stability[0127]After agingfor 300 hours at 1050°C, no TCPphase is observed for Ex6superalloyby scanning electron microscopy image analysis.[0128]Sensitivity to foundry defect formation[0129]After forming by the lost-wax process and directional 10solidification in the Bidgman furnace, no defects resulting from the casting process, particularly of the “freckles”type,were observed inthe Ex2, Ex5, Ex6 and Ex10superalloys. The“freckles”type defects are observed after immersion of the specimen in a solution based on HNO3/H2SO4.[0130]Although the present disclosurehas been described with 15reference to a specific example of a specific embodiment, it is obvious that various modifications and changes can be made to these examples without going beyond the general scope of the invention as defined by the claims. In addition, individual features of the different embodiments referred to may be combined in additional embodiments. Therefore,the 20description and drawings should be considered in an illustrative rather than restrictive sense.
21CLAIMS1.A nickel-based superalloy comprising, in percentages by mass,4.0 to 5.5% rhenium, 3.5 to 12.5% cobalt, 0.30 to1.50%molybdenum, 3.5 to 5.5% chromium, 3.5 to 5.5% tungsten, 4.5to 6.0% aluminum, 50.35 to 1.50% titanium, 8.0 to 10.5% tantalum, 0.15 to 0.30%hafnium, 0.05 to 0.15% silicon, the balance being nickel and unavoidableimpurities.2.The superalloyaccording toclaim1, comprising, in percentages by mass,4.0 to 5.5% rhenium, 3.5 to 8.5%cobalt, 0.30 to1.50%10molybdenum, 3.5 to 5.5% chromium, 3.5 to 4.5% tungsten, 4.5to 6.0% aluminum, 0.50to 1.50% titanium, 8.0 to 10.5% tantalum, 0.15 to 0.30% hafnium, 0.05 to 0.15% silicon, the balance being nickel and unavoidableimpurities.3.The superalloyaccording toclaim1, comprising, in percentages 15by mass,4.0 to 5.5% rhenium, 3.5 to 12.5% cobalt, 0.30 to1.50%molybdenum, 3.5 to 5.5% chromium, 3.5 to 5.5% tungsten, 5.0to 6.0% aluminum, 0.35 to 1.50% titanium, 8.0 to 10.5% tantalum, 0.15 to 0.30% hafnium, 0.05 to 0.15% silicon, the balance being nickel and unavoidableimpurities.204.The superalloyaccording to claim1, comprising, in percentages by mass,4.5 to5.5% rhenium, 4.0to 6.0%cobalt, 0.30 to 1.00%molybdenum, 3.5 to 4.5%chromium, 3.5 to 4.5% tungsten, 4.5to 6.0% aluminum, 0.50to 1.50% titanium, 8.0 to 10.5% tantalum, 0.15 to 0.30% hafnium, 0.05 to 0.15% silicon, the balance being nickel and unavoidable25impurities.5.The superalloyaccording to claim1, comprising, in percentages by mass,4.5to 5.5% rhenium, 3.5 to 12.5% cobalt,0.50 to1.50%molybdenum, 3.5 to 4.5%chromium, 3.5 to 4.5% tungsten, 5.0to 6.0% aluminum, 0.50to 1.50% titanium, 8.0 to 9.0%tantalum, 0.15 to 0.30% 30hafnium, 0.05 to 0.15% silicon, the balance being nickel and unavoidableimpurities.6.The superalloyaccording to claim1, comprising, in percentages by mass,4.5 to5.5% rhenium, 7.0to 9.0%cobalt, 0.50 to 1.50%molybdenum, 3.5 to 4.5%chromium, 3.5 to 4.5% tungsten, 5.0to 6.0% 35aluminum, 0.50to 1.50% titanium, 8.0 to 9.0% tantalum, 0.15 to 0.30%
22hafnium, 0.05 to 0.15% silicon, the balance being nickel and unavoidableimpurities.7.The superalloyaccording to claim1, comprising, in percentages by mass,4.2 to5.3%rhenium, 6.0to 8.0%cobalt, 0.30 to 1.00%molybdenum, 3.5 to 4.5%chromium, 4.5 to5.5% tungsten, 5.0to 6.0% 5aluminum, 0.35 to 1.30% titanium, 8.0 to 9.0%tantalum, 0.15 to 0.30% hafnium, 0.05 to 0.15% silicon, the balance being nickel and unavoidableimpurities.8.The superalloyaccording toclaim1, comprising, in percentages by mass,4.0 to 5.0%rhenium, 4.0 to 6.0%cobalt, 0.30 to 1.00%10molybdenum, 4.5 to5.5% chromium, 3.5 to 4.5% tungsten, 5.0to 6.0% aluminum, 0.35 to 1.30% titanium, 8.0 to 10.5% tantalum, 0.15 to 0.30% hafnium, 0.05 to 0.15% silicon, the balance being nickel and unavoidableimpurities.9.The superalloy according to claim1, comprising, in percentages 15by mass, 5.2%rhenium, 5.0%cobalt, 0.50%molybdenum, 4.0%chromium, 4.0%tungsten, 5.4%aluminum, 1.00% titanium, 8.5% tantalum, 0.25%hafnium, 0.10%silicon, the balance being nickel and unavoidableimpurities.10.The superalloy according to claim1, comprising, in percentages 20by mass, 5.2% rhenium, 5.0% cobalt, 0.50% molybdenum, 4.0% chromium, 4.0% tungsten, 5.4% aluminum, 1.00% titanium, 8.5% tantalum, 0.17% hafnium, 0.10% silicon, the balance being nickel and unavoidable impurities.11.The superalloyaccording toclaim1, comprising, in percentages 25by mass,5.2% rhenium, 5.0% cobalt, 0.50% molybdenum, 4.0% chromium, 4.0% tungsten, 5.1%aluminum, 1.00% titanium, 10.0%tantalum, 0.25% hafnium, 0.10% silicon, the balance being nickel and unavoidableimpurities.12.The superalloyaccording toclaim1, comprising, in percentages 30by mass,5.0%rhenium, 12.0%cobalt, 1.00% molybdenum, 4.0% chromium, 4.0% tungsten, 5.4% aluminum, 1.00% titanium, 8.5% tantalum, 0.25% hafnium, 0.10% silicon, the balance being nickel and unavoidableimpurities.13.The superalloyaccording toclaim1, comprising, in percentages 35by mass,5.0%rhenium, 4.0%cobalt, 1.00% molybdenum, 4.0%
23chromium, 4.0% tungsten, 5.4% aluminum, 1.00% titanium, 8.5% tantalum, 0.25% hafnium, 0.10% silicon, the balance being nickel and unavoidableimpurities.14.The superalloy according toclaim1, comprising, in percentages by mass, 4.9%rhenium, 8.0% cobalt, 1.00%molybdenum, 4.2%5chromium, 4.0% tungsten, 5.4% aluminum, 1.00% titanium, 8.5% tantalum, 0.25% hafnium, 0.10% silicon, the balance being nickel and unavoidableimpurities.15.The superalloy according toclaim1, comprising, in percentages by mass, 4.9% rhenium, 8.0% cobalt, 1.00% molybdenum, 4.2% 10chromium, 4.0% tungsten, 5.4% aluminum, 1.00% titanium, 8.5% tantalum, 0.17% hafnium, 0.10% silicon, the balance being nickel and unavoidable impurities.16.The superalloy according toclaim1, comprising,in percentages by mass, 4.9% rhenium, 8.0% cobalt, 1.00% molybdenum, 4.2% 15chromium, 4.0% tungsten, 5.4% aluminum, 1.00% titanium, 8.5% tantalum, 0.16% hafnium, 0.10% silicon, the balance being nickel and unavoidable impurities.17.The superalloy according toclaim1, comprising, in percentages by mass, 4.7%rhenium, 7.0% cobalt, 0.50% molybdenum, 4.0% 20chromium, 5.0% tungsten, 5.4% aluminum, 0.80% titanium, 8.5% tantalum, 0.25% hafnium, 0.10% silicon, the balance being nickel and unavoidableimpurities.18.The superalloy according toclaim1, comprising, in percentages by mass, 4.5%rhenium, 5.0% cobalt, 0.50% molybdenum, 5.0% 25chromium, 4.0% tungsten, 5.4% aluminum, 1.00% titanium, 8.5% tantalum, 0.25% hafnium, 0.10% silicon, the balance being nickel and unavoidableimpurities.19.The superalloy according toclaim1, comprising, in percentages by mass, 4.5%rhenium, 5.0% cobalt, 0.50% molybdenum, 5.0%30chromium, 4.0% tungsten, 5.4% aluminum, 0.55%titanium, 10.0%tantalum, 0.25% hafnium, 0.10% silicon, the balance being nickel and unavoidableimpurities.20.The superalloy according toclaim1, comprising,in percentages by mass, 4.3% rhenium, 5.0% cobalt, 0.50% molybdenum, 4.0% 35chromium, 4.0% tungsten, 5.4% aluminum, 1.00% titanium, 8.5%
24tantalum, 0.25% hafnium, 0.10% silicon, the balance being nickel and unavoidable impurities.21.Asingle-crystal blade (20A, 20B) for a turbomachine comprising a superalloy according toany oneof claims 1 to 20.22.Theblade (20A, 20B) according toclaim21,comprising a 5protective coating comprising a metallicbond coatdeposited on the superalloy and a ceramic thermal barrierdeposited on the metallicbond coat.23.Theblade (20A, 20B) according toclaim21 or 22,having a structure oriented in a<001>crystallographic direction.1024.A turbomachine comprising a blade (20A, 20B) according toany oneof claims21 to23.