WEAR AND MECHANICAL PROPERTIES OF IN SITU A356/5%TiB2 COMPOSITE SYNTHESIS BY COOLING SLOPE TECHNIQUE

The main aim of this study is to understand the microstructure characterization, mechanical properties and wear behavior of in situ processed A356/5%TiB2 rheocast metal matrix composite. This investigation deals with an aluminum-based in situ composite wherein the reinforcement, TiB2, was synthesized in the molten alloy via reaction of salts between K2TiF6 and KBF4. The paper shall cover a few aspects of this new generation of composites, such as the development of in situ composite and distribution pattern (grain structure), size and number of TiB2 in cast ingot of A356 aluminum alloy with 5% TiB2. The obtained results revealed that cast condition of A356/TiB2 composite, primary phase of aluminum alloy and eutectic Si phase are normally in the refined shape and TiB2 particles are mostly in the hexagonal or near spherical shape, with the size ranging from size 1 to 5 mu m uniformly distributed throughout the microstructure. It has been found that the mechanical properties of rheocast composite material are enhanced with addition of TiB2 particles. The wear rate of the composites improves significantly with the TiB2 content. Analysis of the worn surfaces suggests that adhesion and ploughing are the predominant wear mechanisms.