A salt base reactive casting process has been employed to produce A356
aluminium casting alloys containing fine dispersions Of TiB2. These h
ave been compared with commercially available Duralcan A356 material w
ith SiC particles which have also been incorporated by a casting techn
ique. Structural, mechanical, and wear properties have been measured.
These show that TiB2 is extremely effective in enhancing modulus in ad
dition 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 fract
ion, as is the load transition from mild to severe wear. However, the
wear mechanisms for TiB2 and SiC composites are different when the ste
el disc is taken into account and the wear debris examined. The plate
is effectively machined by SiC, resulting in extensive damage of the m
ating plate. Alloy A356 with TiB2 additions is made by reactive castin
g a simple alloy to process and is thereby a viable alternative to low
cost Al-SiC cast composites. (C) 1993 The Institute of Materials Manu
script received 2 March 1993; in final form 5 May 1993.