Synthesis and Properties of Discontinouosly Reinforced Aluminum Matrix Composites

Abstract

Due to the very high performance requests, a new type of, so called, "high tech" materials which are used in aircraft, rocket or automobile industry, need to have a good combination of properties under static and dynamic loading. One group of materials that can meet such requirements are metallic composites which consist of the metallic matrix (metal or alloy) reinforced whit whiskers or directionally oriented fibers of secondary phase. Currently, there are many different composite materials available, enabling one to easily select the most suitable combination of metallic matrix and reinforcing phase, depending on the uniquely defined application requests. By selecting proper type of matrix and suitable chemical composition, shape and the amount of reinforcing phase, many composites with different mechanical properties can be produced. Potential application of such materials is very wide, but the limiting factor is still their quite high price due to the complexity of their production. In the last two decades there was an intense development of one class of composites with aluminum alloy matrix best known as the discontinuously reinforced aluminum materials (DRA). These materials consist of aluminum alloy matrix reinforced by ceramic particles. Although, DRA composites can be produced in many ways, powder metallurgy technique offers the best results. This article presents results of both fundamental and development studies of sintered composite materials with the Al-Zn-Mg-Cu matrix and the SiC reinforcing phase, conducted in last couple of years. As this is the composite which is already commercially applied or on the verge of being applied, all gathered results are thoroughly analyzed from the aspects of its synthesis, microstructure and several mechanical and fracture properties.