Effect of the Thermal Expansion Characteristics of Reinforcements on the Electrical Wear Performance of Copper Matrix Composite

摘要

Copper matrix composites reinforced with MgO, Al_2O_3, SiO_2, and SiC nanoparticles were fabricated by powder metallurgy. The tribological properties of the composites were examined using a self-made pin-on-disk electrical wear tester. Thermal expansion properties of the prepared composites were evaluated by their coefficient of thermal expansion from 50 to 500℃. The effect of the thermal expansion characteristics of reinforcements on the electrical wear performance of the composites was also studied. The results showed that the wear rates of MgO/Cu and Al_2O_3/Cu composites were lower than those of SiC/Cu and SiO_2/Cu composites, which were also consistent with the difference between the coefficient of thermal expansion of the copper matrix and reinforcements. The relationship was analyzed by calculation of the thermal stress at the copper matrix-reinforcement interface in the electrical sliding process. Microstructural observation revealed that the wear mechanisms of the copper matrix composites were mainly adhesive wear and plastic deformation accompanied by a small amount of arc damage.