Properties of reactively cast aluminium–TiB2alloys

Abstract

A salt base reactive casting process has been employed to produce A356 aluminium casting alloys containing fine dispersions of TiB₂. These have been compared with commercially available Duralcan A356 material with SiC particles which have also been incorporated by a casting technique. Structural, mechanical, and wear properties have been measured. These show that TiB₂ is extremely effective in enhancing modulus in addition to significantly reducing the coefficient of friction when used against an alloy steel plate. The wear rate of the alloy is found to be independent of particle type but is governed mainly by volume fraction, as is the load transition from mild to severe wear. However, the wear mechanisms for TiB₂ and SiC composites are different when the steel disc is taken into account and the wear debris examined. The plate is effectively machined by SiC, resulting in extensive damage of the mating plate. Alloy A356 with TiB₂ additions is made by reactive casting a simple alloy to process and is thereby a viable alternative to low cost Al–SiC cast composites. MST/1854