Performance of Al-5Ti-1B master alloy after ball milling on minimizing hot tearing in Al-7Si-3Cu alloy

Abstract

Hot tearing of Al–7Si–3Cu alloys with addition of as received Al–5Ti–1B grain refiner and ball milled grain refiner have been studied with constrained mould casting to investigate the effect of these additions on hot tear resistance. Al–5Ti–1B master alloy contains TiAl3 and sub-microscopic TiB2 particles of sizes, 20–80 and 0.5–2 µm respectively. After ball milling of Al–5Ti–1B master alloy, TiAl3 particles get reduced in size from 80 to 9 µm. Thus the number of finer TiAl3 particles increases, resulting in improvement of grain refining performance of the grain refiner and thus eliminating hot tearing.