Heat treatment and wear characteristics of Al/SiCP composites fabricated by duplex process

This study was undertaken to investigate the effects of alloying elements and heat treatment on the microstructures, wear resistance, and heat resistance of Al-Si-Cu-Mg-(Ni)/SiCp composites fabricated by a duplex process that consists of squeeze infiltration (1st step) followed by squeeze casting (2nd step). This duplex process produces a homogeneous distribution of SiCp in Al alloy. The hardness of the composites increased with decrease in SiCp size, and also with Ni addition in both the as-cast and the as-aged specimens. Compared with 5 and 10 mum SiCp reinforced Al composites, the aging time to obtain the peak hardness was shortened for 3 mum SiCp reinforced Al composite, because of higher density dislocations on the periphery of SiCp in the matrix. However, the Al composite reinforced with 10 mum SiCp was found to have the lowest wear amount as compared with 3 and 5 mum SiCp composites. The amount of wear in Al/SiCp composites decreased with increase of the sliding speed because abrasive wear occurred under low sliding speed and block-type wear debris occurred under high sliding speed. (C) 2003 Elsevier Ltd. All rights reserved.