Description:Field of Invention
The present invention relates to, development of Metal Matrix Composite with reinforcement for various applications such as Aerospace, Automobile etc. The Invention comprises Aluminum Metal Matrix and Graphene as reinforcement.
Objectives of Invention
The objective of this invention is to develop a metal matric composite to improve the life cycle of aerospace and automobile structures operating at various conditions by improving the structural and mechanical characteristics of the material.
Background of the Invention
With the use of composite technology, various materials, including metals, polymers, ceramics, and the like, can be combined to create multi-layered structures with unique features not possible with a single material. These enhanced composite features typically include many other characteristics as well as mass, strength, wear resistance, heat resistance, electrical, magnetic, optical, and/or power densities. Aluminum alloys and its derived composites are seen as possible substitute lightweight materials for aerospace applications. Additionally, due of their high strength, easy availability, low cost, low density, heat treatability, workability, and retention of fracture toughness even at cryogenic temperatures, they have attracted a lot (Hirsch J. [2011], Aluminium in innovative light-weight car design, Materials Transactions, 52, 818–824). Aluminium-based MMCs (AMMCs) are accounted for about 69% of mass annually for various industrial uses such as aviation, automobiles, electronic devices, marine industries and space shuttles (Muhammad Yasir Khalid et al [2023], Review of recent trends and developments in aluminium 7075 alloy and its metal matrix composites (MMCs) for aircraft applications, Results in Engineering, Volume 20, 101372). Aluminum 7075 alloys are often regarded as a practical option for substituting several other aluminum alloys like 2014, 2024, and 2017 in numerous important applications due to their exceptional stress corrosion resistance (M. Imran and A.R.A. Khan [2019], Characterization of Al-7075 metal matrix composites: a review Journal of Materials Research and Technology, Volume 8, Issue 3, Pg 3347-3356). On the other hand, graphene is a 2-D, single atomic layer of connected carbons and has a much higher load transfer capacity than traditional carbon-based nano-reinforcements (Lee, C et al, [2008], Measurement of the elastic properties and intrinsic strength of monolayer graphene. Science, 321, 385–388).
Recent studies show that, Al 7075 is the most widely used alloy for aircraft structures along with Al 2024. The complete potential of nanoparticles has been extensively harnessed through a range of fabrication methods up to now. The inclusion of ceramic nanoparticles using the stir casting process notably enhanced the mechanical characteristics of aluminium 7075-based MMC, particularly from the perspective of the aerospace sector.
Friction Stir Processed (FSP) aluminum metal matrix composites with SiC particles improved hardness by 50% and that of yield strength by 2.5 times (Owa, T. et al [2021], Mechanical Behavior of Graphite-Reinforced Aluminum Alloy Composite via Friction Stir Processing. Materials Transactions, 62, 519–525). The development of AMCs with tailored properties relies heavily on the homogeneous distribution of reinforcement in the Al matrix. In a similar vein, getting the right qualities from the manufactured AMCs is facilitated by selecting a production procedure and its process parameters optimally (Khan M et al [2018], Effect of inter-cavity spacing in friction stir processed Al 5083 composites containing carbon nano tubes and boron carbide particles. J Material Process Technology, 253, 72-85).
Research has primarily concentrated on utilizing powder fabrication techniques to achieve a more refined grain, impact of size and consistent blending. Nevertheless, limited research has delved into the impact of quantity of hybrid reinforcement produced through high-speed ball milling in conjunction with FSP.
Numerous research studies have concentrated on creating silicon carbide (SiC)/Graphite aluminum composites through various methods such as stir-casting, squeeze casting, in-situ, semi-solid powder densification, and spray co-deposition. However, the literature rarely mentions the powder metallurgy route with A17075 as the metal matrix and SiC-Gr as the combination of reinforcement (AU2021106706A4). Recent reports have outlined the synthesis of graphene reinforced aluminum matrix composites, utilizing liquid methods, ball milling plus hot isostatic pressing, hot pressing or hot extrusion, ball milling plus sintering, sintering or sintering plus extrusion, spark plasma sintering, or sonication plus friction stir processing (CN113088763A). Additionally, Powder metallurgy (PM) technique has been highlighted in other studies as a versatile process for manufacturing nano-MMC's due to its simplicity, flexibility, and net-shape capability (WO2016193974A1). These studies also conclude that there are certain major problems while fabricating the graphene reinforcing MMCs such as maintaining the structural integrity and uniformity of graphene complexity of mixing, etc (CN113088763A).
As a result, there is still work to be done to find a straightforward and uniform method for manufacturing graphene-reinforced aluminum matrix composite materials.
Summary of the invention
The present invention discloses aluminum-based Metal matrix composite reinforced with graphene. The main goal of this innovation is to offer techniques, platforms, and procedures for creating metal matrix composite structures with improved mechanical characteristics at a reduced production expense compared to the existing cutting-edge technology. The aim of the invention is to improve the mechanical properties of the existing aluminum MMC by considering various combinations of graphene.
Detailed description of the invention
The invention involves three components, Alumina, graphene and stir casting.
Alumina, also known as aluminum oxide, is a synthetic compound with the chemical formula Al2O3. It is a white or nearly colorless crystalline substance. Activated alumina is a porous, granular material used as a catalyst substrate and as an adsorbent for removing water from gases and liquids. It possesses the characteristic properties of alumina, such as low electrical conductivity, resistance to chemical corrosion, high strength, and extreme hardness.
Graphene is essentially a single layer of graphite, a carbon allotrope with a hexagonal lattice structure, whaich sets graphene apart is its sp2 hybridization and incredibly thin atomic thickness of 0.345 nm. These unique properties allow graphene to achieve remarkable strength, electrical conductivity, and heat conduction, surpassing many other materials. Let's delve into the exceptional qualities of graphene, exploring what makes it stand out from other carbon forms and 2D crystalline compounds.
Stir casting involves the stirring of molten metals to continuously mix particles into a metal alloy, which is then poured into a sand mold, cooled, and solidified. Research indicates that the speed of stirring, duration of stirring, and stirring temperature are key factors that impact the quality and uniformity of the metal matrix composite (MMC).
The process involves mixing of Al7075, graphene and Al203. These are mixed with weight fractions of Al7075 97%, graphene 2.5% by weight and rest is Al203. The First step involves the cleaning of crucible and heating it to temperature of 200 0C.
In the next step, add Al7075 to the crucible and heat it upto 720 0C. Now, add the Silicon Carbide and Alumina to the heated Al7075. Increase the temperature to 750 0C. After this, start stirrer to operate at 100 rpm. Now stir it for 10 min until the mixture is properly mixed with uniformity.
Now, pour the molten material into die of required shape and let it cool down. After cooling, machine it to the required shape and dimensions.
Tensile Testing, the specimens have been selected. It is important to ensure that they do not exhibit any notching or cracks from the manufacturing process, nor any surface defects that could negatively impact the tensile tests.
Prior to placing the specimens into the Instron machine, the computer system linked to the machine was configured by entering the necessary information regarding the gauge length and width of the specimen. Subsequently, the computer system was readied to capture data and generate required load-deflection graphs. The specimens were then inserted into the Instron machine, and a tensile test was conducted. The data was electronically recorded in text files, and the load-deflection curve was displayed on the computer screen in visual form. It was found that the tensile strength of has been improved by 79% when compared to that of the aluminum alloy Al7075. It was also observed that the strength to weight of the specimen has also improved by 15% which is acceptable in aeronautical and aerospace applications.
Ultrasonic Testing uses sound waves which have a frequency exceeding 2 MHz, providing them with strong penetrating capabilities due to their high frequency. The directional nature of high frequency sound waves allows them to pass through a medium such as steel or plastic until they reach a boundary with another medium like air, at which point they bounce back to the source. By analyzing these reflections, it is possible to gauge the thickness of a test piece or uncover evidence of cracks or other concealed internal flaws. During this NDT process, a diagnostic machine-connected ultrasound transducer is moved over the material or object being examined. A couplant such as oil is used to separate the transducer from the test object, as in immersion testing.
3 Claims & 4 Figures

Brief description of Drawing
In the figures which are illustrate exemplary embodiments of the invention.
Figure 1 Image of Reinforcement and Stir Casting Machine (a) Graphene Nano filler powder and (b) Alumina Oxide Powder c) Schematic of Stir casting Machine
Figure 2 Pouring of Molten metal into Mould
Figure 3 Testing Setup: a) Test Specimen per ASTM Standards; b) Schematic of UTM.
Figure 4: Ultrasonic Inspection: a) Schematic of Ultrasonic Testing and b) Internal flaws of Material shown by Ultrasonic Testing
Detailed description of the drawing
As described above the present invention relates to development of a metal matrix composite with elevated Mechanical properties such as tensile strength, hardness, etc.
The raw material used for the preparation of the composite are shown in figure1 a) and 1b). Graphene L powder is shown in Figure 1 a) and hat of Alumina is shown in Figure 1 b). Figure 1 c) shows Stir casting setup which is used for continuously stirring particles into metal alloy to melt such that all the particles are uniformly mixed.
The molten mixture is poured into the mould of required shape. Figure 2 represents the molten material being transferred from the crucible to rectangular mould. The material is allowed to cool at room temperature and then removed from the mould. The material is then transferred to the machining unit where it is reduced to required size and shape as per the standards required for testing. Figure 3 a) represents the test Specimen used for the tensile testing to predict the mechanical characteristics. Figure 3 b), represents a schematic of UTM used for tensile testing.
The material is inspected for internal flaws and defects using Ultrasonic testing machine whose schematic is shown in figure 4 a) along with the results of the inspection in figure 4 b) ,

Claims:The scope of the invention is defined by the following claims:

Claim:
1. A method to improve the mechanical properties of Metal matrix composite with nano fillers comprising,
a) The major constituents are Al7075 at 97%, graphene at 2.5% by weight, and the remainder Al203
b) The Al7075 is heated to temperature of 720 0C for melting and ensuring the liquid is easily absorbing the additives.
c) The SiC and Alumina are added to the molten Al7075 at 720 0C which ensures SiC and Alumina to mix properly with molten Al7075.
2. According to Claim 1, the stir casting ensures the composition is uniformly achieved over the complete mixture of molten combination.
3. As per Claim 2, the molten mixture is poured into a mould and then fabricated to the required shape and size.