Mechanical and tribological behavior of the metal matrix composite AA6061/ZrO2/C

This study investigates the influence of zirconium dioxide (ZrO2) and graphite (C) on the mechanical and tribological behavior of aluminum-based metal matrix composite (AA6061) fabricated through the stir casting. Metal matrix composites (MMC) are prepared with the following weight percentages: 100 % AA; 96 % AA-2 % ZrO2-2 % C; 88 % AA-6 % ZrO2-6 % C; 92 % AA-6 % ZrO2-2 % C; and 96 % AA-2 % ZrO2-6 % C. The microstructure and the mechanical and tribological behavior are characterized, and their correlations are obtained. Microstructural studies of the MMC reveal a uniform distribution of ZrO2 and C particles in the AA6061 matrix. The addition of ZrO2 improves the hardness from 6 % to 12 % (30 HRC to 40.94 HRC) and the ultimate tensile strength from 8 % to 15 % (128 MPa to 166.3 MPa) of the base metal (AA6061). The tribological behavior of wear and the frictional properties of the MMC are also studied by performing dry sliding wear test using pin-on-disc method. Result shows that the minimum and maximum wear rates of MMC are 5 E-9 and 6.2 E-9 (g/mm), respectively, at speed of 850 rpm and constant sliding distance of 1000 m.