Effect of T6 Heat Treatment on A356 Aluminium Alloy and A356 Composite Containing Titanium Diboride Obtained by semisolid casting
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Date
2016-06
Authors
Nurul Atikah Mohamad Zulkamal
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Abstract
The aim of this project is to study the effect of T6 heat treatment on semisolid A356 alloy and semisolid A356 composite containing 1.5 wt.% and 2.63 wt.% TiB2. The solution treatment was carried out at different temperatures (500˚C, 520˚C and 540˚C) and various time (0.5 hour, 1 hour, 2 hours and 5 hours). Then, age hardening was conducted at different temperature (120˚C, 150˚C and 180˚C) for 8 hours. Both A356 alloy and composite were characterized for microstructure, phases, elemental present, wear morphology, microhardness and wear properties using optical microscope, X-ray diffraction, scanning electron microscope equipped with energy disperse X-ray, Vickers microhardness and pin-on-disc tribometer. Higher solution treated temperature and time (540˚C, 5h) resulted in finer size of Si particles for semisolid A356 alloy. Microhardness of solution treated semisolid A356 alloy achieved higher hardness at 540˚C and soaking time of 5 h with hardness value of 75.16 HV. Microstructure of semisolid A356 composite containing TiB2 was refined with higher addition of TiB2. Solution treated of semisolid A356 composite containing 1.5 wt.% TiB2 has the smallest Si particles and the highest hardness of 119.7 HV. Further aging of A356-1.5 wt.% composite at 180°C increased the microhardness to 129.7 HV. Wear resistance of semisolid A356 alloys were improved by addition of TiB2 Wear surface morphology revealed that the adhesive.