Abstract: Mechanical properties were tested for in situ TiB2/A357 composite fabricated by LSM (mixed salts reaction) method. Microstructures of as cast and plastic deformed TiB2/A357 were investigated. The results show that there is a low misfit between (200)A1 and (101)TiB2 with [011^-]A1 // [1O1^- ]TiB2. There is a change from fully den-dritic structure of the α-Al of A357 to a rosette-type structure of TiB2/A357. Sig-nificant increases in proof stress and Young's modulus can be obtained at low TiB2 additions. There exist dislocation loops around neighboring TiB2 particles with about 0.1μm in diameter and dislocation multivlication near TiB2 particles.

Key words: TiB2/Al, in situ, composite,