Aerospace Industry and Aluminum Metal Matrix Composites

Researchers have turned to search for new materials that will meet all the aerospace industry requirements. When it is almost impossible to achieve this with a single material, composite materials have been studied, and there have been great developments in this field. Many elements are used in aircraft construction, but aluminum is the most preferred due to its low density, good castability, high strength, corrosion resistance, and good fatigue strength. However, its strength and stiffness limit its usability. To solve this problem, aluminum is combined with various elements. Aluminum metal matrix composites are an example of this. Aluminum metal matrix composites are preferred in aircraft applications due to their high specific modulus and good mechanical and thermal properties. This review provides information on the use of aluminum metal matrix composite materials in the aerospace industry.

Numerical validation of thermal conductivity of Al6061 based hybrid nano metal matrix composite filled with nanoparticles of Ni and Cr

Aluminum composite matrix materials are regarded as the most popular type of composite materials. Metal matrix composites made of aluminum have better mechanical and thermal properties, including a higher strength-to-weight ratio, tensile strength, hardness, and a low coefficient of thermal expansion. In various types of applications viz., automobile, aviation, the thermal characterization of aluminum metal matrix composites has increased. Thermal conductivity as a function of temperature, thermal diffusivity, and the thermal gradient is one of the essential thermal characteristics of aluminum metal matrix composites needed to understand the material's behavior. The current work evaluated thermal conductivity as a product of thermal diffusivity, density, and specific heat for Al6061/Ni/Cr hybrid nano metal matrix composites from 50°C to 300°C. Al6061 based metal matrix composite reinforced with varying wt.% of Ni and Cr nanoparticles whereas fixed wt.% of graphene and Mg added to improve thermal conductivity, self-lubrication, and wettability. Thermal diffusivity, specific heat, and density were evaluated using laser flash apparatus (LFA 447), differential scanning calorimetry (DSC), and Archimedes principle, respectively. Results revealed that the thermal conductivity of fabricated composites increases with Ni, Cr, Mg, and graphene nanoparticles. With further expansion of reinforced particles of Ni and Cr, the thermal conductivity decreases. Finite element analysis (FEA) has been conducted to determine the thermal gradient and thermal flux using experimental values such as density, thermal conductivity, specific heat, and enthalpy at various temperature ranges to validate the experimental results.

Corrosion of Aluminum Metal Matrix Composites: A Review of the Effect of Manufacturing Processes, Processing Routes and Secondary Phases

The vulnerability of Al matrix composites to general and preferential corrosion is due to the intrinsic proneness of binary materials to undergo advanced deterioration. Control of the prevalent sites for evolution and proliferation of confined corrosion strongly influence the corrosion resistance of the composites. The problem for enhanced utilization of composites, has exacerbated with attention on the productive life and resilience to environmental degeneration during operational service. This can be achieved through proper comprehension of the electrochemical mechanism, the intriguing nature of SiC grains and their importance on the secondary phases, metallurgical configuration, and manufacturing process routes. This review confirms the relevance of secondary phases, microstructures and manufacturing processes in relation to SiC particles on the corrosion invulnerability of Al matrix composites to further add corrosion mitigation in design and and technological advancement.

A review on in-situ aluminum metal matrix composites manufactured via friction stir processing: meeting on-ground industrial applications

Purpose In-situ aluminum metal matrix composites (AMMC) have taken over the use of ex-situ AMMC due to the generation of finer and thermodynamically stable intermetallic compounds. However, conventional processing routes pose inevitable defects like porosity and agglomeration of particles. This paper aims to study current state of progress in in-situ AMMC fabricated by Friction Stir Processing. Design/methodology/approach Friction stir processing (FSP) has successfully evolved to be a favorable in-situ composite manufacturing technique. The dynamics of the process account for a higher plastic strain of 35 and a strain rate of 75 per second. These processing conditions are responsible for grain evolution from rolled grain → dislocation walls and dislocation tangles → subgrains → dislocation multiplication → new grains. Working of matrix and reinforcement under ultra-high strain rate and shorter exposure time to high temperatures produce ultra-fine grains. Do the grain evolution modes include subgrain boundaries → subgrain boundaries and high angle grain boundaries → high angle grain boundaries. Findings Further, the increased strain and strain rate can shave and disrupt the oxide layer on the surface of particles and enhance wettability between the constituents. The frictional heat generated by tool and workpiece interaction is sufficient enough to raise the temperature to facilitate the exothermic reaction between the constituents. The heat released during the exothermic reaction can even raise the temperature and accelerate the reaction kinetics. In addition, heat release may cause local melting of the matrix material which helps to form strong interfacial bonds. Originality/value This article critically reviews the state of the art in the fabrication of in-situ AMMC through FSP. Further, FSP as a primary process and post-processing technique in the synthesis of in-situ AMMC are also dealt with.

Sintering Bonding of SiC Particulate Reinforced Aluminum Metal Matrix Composites by Using Cu Nanoparticles and Liquid Ga in Air

SiC particulate reinforced aluminum metal matrix composites (SiCp/Al MMCs) are characterized by controllable thermal expansion, high thermal conductivity and lightness. These properties, in fact, define the new promotional material in areas and industries such as the aerospace, automotive and electrocommunication industries. However, the poor weldability of this material becomes its key problem for large-scale applications. Sintering bonding technology was developed to join SiCp/Al MMCs. Cu nanoparticles and liquid Ga were employed as self-fluxing filler metal in air under joining temperatures ranging from 400 °C to 500 °C, with soaking time of 2 h and pressure of 3 MPa. The mechanical properties, microstructure and gas tightness of the joint were investigated. The microstructure analysis demonstrated that the joint was achieved by metallurgical bonding at contact interface, and the sintered layer was composed of polycrystals. The distribution of Ga was quite homogenous in both of sintered layer and joint area. The maximum level of joint shear strength of 56.2 MPa has been obtained at bonding temperature of 450 °C. The specimens sintering bonded in temperature range of 440 °C to 460 °C had qualified gas tightness during the service, which can remain 10−10 Pa·m3/s.