Introduction
Advanced metal matrix composites (AMMCs) consisting of matrix, reinforcing fibers and various other constituents have gained enormous attention due to their remarkable mechanical and physical properties, as compared to traditional metal alloys. Today, there is a growing demand for high-performance metal matrix composite materials that can be employed in aerospace, automotive, marine,and nuclear engineering applications. In particular, the demand for a highly strength, stiff and light metal matrix composite materials for manufacturers to use in their production of cars and airplanes, for instance, is increasing.
Apart from mechanical properties, another important factor when selecting metal matrix composite materials is the corrosion resistance of the material. Multiphase metal composites can have varied microstructures and properties; therefore, it is necessary to have a comprehensive understanding of the chemical components, interactions, and dynamic influences that a certain AMMC may encounter in a potential application.
High temperature environments and enhanced fatigue resistance are areas where AMMCs tend to be highly advantageous. High temperature materials, such as AlSi, AlMg and AlSiC, offer higher strength, creep resistance, and erosion resistance at elevated temperatures. Another example is, AlTiB, which is a higher strength lightweight all-aluminum alloy matrix composite reinforced by a combination of titanium and boron fibers. All these nanocomposites can resist heat up to approximately 1200°C and are usually used to construct heat shields, rockets and supersonic missiles, aircraft and turbine engines.
To improve the moisture resistance of aluminum and magnesium alloys, AMMCs are also often treated with thermal diffusion. This involves the diffusion of elements such as zirconium, titanium, boron, and chromium from a substrate coating onto the surface of the substrate. The combination of the diffusion of these elements and the presence of the interfacial layer created by the contaminants tend to increase the overall corrosion resistance of the material.
The wide range of advantages of high temperature and corrosion-resistant AMMCs become even more evident with specific treatments, such as surface modification treatments or through heat treatment as a means of improving the quality and performance of AMMCs. The surface modification treatments, such as sol-gel coating of the reinforcing phase, XPS surface analysis, and post-treatment anodization can give the AMMC enhanced mechanical and tribological properties. Similarly, the use of electron-beam welding has been found to be an effective technique for joining multiphase metal composites. The solid-state diffusion of metals such as aluminum, magnesium, and titanium increases the mechanical properties of these materials.
Conclusion
AMMCs are advanced composite materials with remarkable mechanical and physical properties. With the addition of certain treatments and treatments, such as sol-gel coating of the matrix phase, XPS surface analysis and post-treatment anodization, AMMCs can have enhanced mechanical and tribological properties. It is also possible to improve the moisture resistance and fatigue resistance of aluminum and magnesium alloys through the use of thermal diffusion treatments. Electron-beam welding is a good technique for joining multiphase metal composites. All of these treatments are improving the functionalities and performance of AMMCs.
