Microstructure and Mechanical Properties of TiC_p/ZA-12 Composites

Abstract

TiCp/ZA-12 composites have been fabricated by XDTM method and stirring-casting techniques. The behavior of TiC particle in the solidification interface has been studied through conventional and directional solidification techniques. The results demonstrate that under conventional solidification conditions, the particles with lower content mainly distribute in eutectic phases; while when at a larger content of TiC particles, they exist both in eutectic phases and in primary phases. Under directional solidification, due to the repulsion of primary phases of alloy on TiC particles, the particles congregate and form band structure, and extent of the congregation in band structure relates to TiC particles content. With the increasing of TiC particles content, their congregation in band structure decreases, and the band structure disappears when the content of TiC particles exceeds 6%. The tests for mechanical properties reveal that the tensile strength and yield strength increase with increasing fraction of TiC particles. When the fraction of TiC particles increase up to 10%, the tensile strength and yield strength are 390MPa and 340MPa, respectively and they increase by 11% and 17% than that of matrix respectively.