EFFECT OF AGING ON ABRASION RATE IN AN AL-ZN-MG-SIC COMPOSITE

The effect of aging on the abrasion rate of an Al-5. 0 wt. % Zn-2. 3 wt. % Mg-7. 5 wt. % SiC composite was investigated and compared with that for Al-5. 0 wt. % Zn-2. 3 wt. % alloy aging at temperatures of 120, 160 and 200 degree C. The results show that aging hardness explicitly determines the abrasion rate of the Al-Zn-Mg alloy with an inverse linear relationship for all treatments. However, in the Al-Zn-Mg-SiC composite, the aging temperature and duration are dominant factors for the abrasion rate. Electron probe microanalysis of the abraded surface indicated that the higher abrasion resistance of the composite is attributable to the stronger interface bonding between SiC particles and the matrix. An anchoring mechanism based on interface precipitation on the surface of the SiC particles and a contraction mechanism based on dimensional contraction of the matrix explain the variation in interface bonding strength and thus the abrasion resistance.