Microstructure and Wear Properties of T6 Heat Treated Semisolid A356-TiB2 composite

Abstract

The aim of this study is to investigate the microstructure and wear properties of T6 heat treated semisolid A356 composite containing 1.5 wt.% and 2.63 wt.% TiB2. The semisolid A356-TiB2 composite was prepared using a cooling slope casting technique. The sample, then was solution treated at different temperatures (500°C, 520°C and 540°C) for 5 hours soaking time. Then, age hardening was conducted at different temperatures (120°C, 150°C and 180°C) for 8 hours. Semisolid A356 composite was characterized for microstructure, microhardness and wear properties. Microstructure of semisolid A356 composite was refined with a higher amount of TiB2. High solution treated temperature (540°C) resulted in the finer size of Si particles in the semisolid A356 alloy. Microhardness of solution treated semisolid A356 alloy achieved higher hardness at 540°C with a hardness value of 75.16 HV. Solution treated of semisolid A356 composite containing 1.5 wt.% TiB2 has the smallest Si particles and the highest hardness of 119.7 HV. Among the samples, A356-1.5 wt.% composite after aging at 180°C showed the highest hardness (129.7 HV). Wear resistance of semisolid A356 alloys was improved by the addition of TiB2. Wear surface morphology revealed that the adhesive and abrasive wear mechanism present.