Abstract
Al_<18>B_4O_<33> whisker and SiC particle and Al_<18>B_4O_<33> particle/whisker reinforced magnesium alloy matrix composites were fabricated by compo casting. The reinforcements distributed uniformly in all composites. By hot-extrusion or squeeze casting in semi-solid condition after compo casting, the pores with several decade and hundred micro-meter in diameter in as-cast composites disappeared, the uniform distribution was remained and the grain size became to be small. In Al_<18>B_4O_<33> whisker /AZ91D composite, the uniform reaction layer 'MgAl2O4' with 10-20nm in thickness formed in compo casting. This layer prevents the direct reaction between the whisker and the matrix in high temperature.
