The Role of Manufacturing Techniques in Reciprocating Wear of Carbide-Reinforced Ni-Co-Cr-Mo-Cu Alloys

Finding the correlation among manufacturing process, microstructure and mechanical properties is critical to design the high-performance alloy. In this study, room temperature ball-on-flat dry sliding wear behavior of carbide-reinforced Ni-Co-Cr-Mo-Cu alloys prepared by hot isostatic pressing (HIP) and hot extrusion (HEX) against Al2O3 ball were investigated. Carbides in the HIP alloy are fine, nearly spherical and have a higher area fraction, in comparison with HEX alloy. Abrasive wear dominates under 10 N load condition, large-sized carbides in HEX alloy display a better resistance to HIP alloy. Oxidative wear dominates under 30 and 50 N load condition, the nearly spherical carbides in the HIP alloy form a stable mixed glaze layer with the fully oxidized alloy surface, lower coefficient of friction (COF) and wear rate were obtained in comparison with HEX alloy. The significant decrease in the wear rate of Al2O3 against HIP alloys under 30 and 50 N load condition is due to the lubricating effect of the oxide glaze layer. The wear rate of the Al2O3 against the HEX alloys almost unchanged due to the insufficient lubrication. It is speculated that the absence of the glaze layer in the HEX alloy is due to the irregular shape of its carbides.