The effect of fibre orientation of the dry sliding wear of borsic-reinforced 2014 aluminium alloy

The effect of fibre orientation on the dry sliding wear of continuous B(SiC) fibre reinforced aluminium alloy composites was investigated using a pin-on-disc wear testing machine. The metal-matrix composites (MMC) samples were tested in the normal (N), parallel (P) and antiparallel (AP) orientations sliding against a steel counter disc at a fixed speed of 1 ms(-1) under loads of from 12 to 60 N. The results showed that for the matrix alloy and MMCs, the average wear increased linearly with load. Wear of the MMCs was insensitive to fibre content but for composites with fibre contents at or above the minimum of 16 vol% used for this work, the wear rate was about 18% of that of the unreinforced matrix. Fibre orientation had a minor effect on wear rate; the N orientation gave the lowest wear rate with the AP orientation slightly higher and the P orientation significantly higher. The average coefficients of friction of the MMCs in N and AP orientations decreased linearly with increased wear rate and non-linearly with increased load, but the P orientation was insensitive to either variable. It was concluded from these results and a metallographic examination that the mechanism of wear of MMCs was essentially oxidative wear of the matrix. The hard fibres modified this to slightly different degrees depending on their orientation relative to the wear surface and sliding direction.