Microstructure and Mechanical Properties of Aluminum Matrix Composites Reinforced With In-Situ TiB2 Particles

Abstract

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The present article investigates the microstructure and mechanical properties of A356 matrix composite reinforced with TiB2 particles synthesized by the salt metal reaction of as-cast and T6 state. Microscopic observations of the prepared composites reveal that in-situ grown TiB2 particles are characterized with regular shapes and nearly uniform distributed in the A356 matrix. A clear interface between the A356 matrix and TiB2 particles was observed. The detailed analysis of mechanical properties of synthesized composites of as-cast and T6 state show that the ultimate tensile strength and Young’s modulus of the synthesized composites increased with the increasing weight percentage (wt%) of in-situ TiB2 particles in the A356 matrix, but the Poisson’s ratio of the synthesized composites decreased with the increase of TiB2 particles wt%. The Young’s modulus of the composites increased by up to 10.8% and the Poisson’s ratio decreased by up to 3.2% with the increase of TiB2 particles wt%, compared to A356 alloy. With the increase of TiB2 particle wt%, the yield strength of the composites decreased at first (when the TiB2 particle wt% is less than 1%) then increased, while elongation and percent reduction in area increased at first and then decreased. Furthermore, T6 heat treatment can refine grain and effectively improve the mechanical properties of composites.

Keywords

• in-situ composites
• A356 alloy
• TiB2
• microstructure
• mechanical properties