Microstructure and High-Temperature Frictional Wear Property of Mo-Based Composites Reinforced by Aluminum and Lanthanum Oxides

In this article, we developed Mo-based composites reinforced with aluminum and lanthanum oxides using a sol-gel method combined with a sintering process and researched the microstructure and frictional wear properties under high-temperature conditions. The microstructure of composites was characterized by -Al2O3 and composite oxide (La0.62Mo0.38)AlO3, which were uniformly distributed in the molybdenum matrix. The composite oxide (La0.62Mo0.38)AlO3 was mainly attached to -Al2O3. The interfaces of -Al2O3/Mo and -Al2O3/(La0.62Mo0.38)AlO3 were well bonded. The -Al2O3 refined the molybdenum grains, increased the relative density and hardness of Mo-based composites, and had an obvious effect on the frictional wear properties of the composites. With increasing -Al2O3 content, the friction coefficient first increased and then decreased, and the wear weight loss decreased continuously. The wear failure mode varied from microcutting to fatigue with increasing -Al2O3 content. The better wear resistance of Mo-based composites, compared to pure molybdenum, was mainly attributed to the characteristics of -Al2O3, such as high microhardness, good morphology, well-bonded phase interface, and high hardness matrix due to the effects of -Al2O3 reinforcement.