Friction And Wear Behavior Of Mg₂B₂O₅Reinforced Aluminum Matrix Composite Materials

The friction and wear properties of Mg2B2O5whisker reinforced6061Al matrixcomposites fabricated via power ultrasonic-stir casting process were investigatedusing a ball-on-disk wear-testing machine against a GCr45steel counterface under drysliding and lubricated conditions. The reinforcements include as-received Mg2B2O5whiskers and Mg2B2O5whiskers coated with CuO and ZnO. The volume fractions ofthe composites were2%.Under dry sliding, the relationship between the wear rate and the coefficient offriction was discussed. Results indicate that the volume wear rate of the Mg2B2O5whiskers coated with ZnO-reinforced aluminum matrix composites was the lowestone among the four materials. As the applied load and sliding speed steadily increasedthe coefficients of friction and wear rates of the as-received matrix alloy and thefabricated composites decreased. As the applied load and sliding speed increased, thewear mechanisms of the composites shifted from a mild to a severe regime.Under lubricated conditions, the relationship between the wear rate and thecoefficient of friction was also investigated. Results indicated that the coefficients offriction of the matrix alloy and the fabricated composites decreased and the wear rateincreased as the applied load and sliding speed steadily increased. Both of the appliedload and sliding velocity of the matrix and composite had critical values, when theapplied loads and sliding velocities reached the critical values, the wear rate increasedsharply and the wear mechanisms of the composites shifted from mild to severeregime.