Wear mechanisms in particle reinforced and laminated metal matrix composites

Wear tests have been performed on SiC particulate reinforced Al alloys and laminated composites of copper/amorphous Ni78Si10B12 using a block-on-ring tester with loads of 9 to 220N and a velocity of approximately 0.1 ms^-1. A metallographic study of the deformation and fracture events which constitute wear has been made. The results indicate that for particle strengthened composites, under abrasive wear conditions, significant improvements in wear resistance can occur relative to aluminum alloys. However, under conditions where the wear process is controlled by cumulative damage events, SiC particles provide nucleation sites for subsurface cracks, and delamination occurs on the scale of particle size resulting in a wear rate similar to that observed in the materials without SiC reinforcement. Sliding wear tests conducted on the laminated composites confirmed that the amorphous layers were effective in increasing the wear resistance of the composite by supporting the load with less deformation and by obstructing the damage process initiated in copper layers.