Microstructure and Wear Resistance of a Novel Mo-Ni-Si System Intermetallic Composite with Ductile Mo Phase

It has been a challenge to improve the toughness of intermetallic compound at low and medium temperatures for developing wear resistance materials. The refractory metals, with a high melting point, strong atomic bonds, high ductility and toughness, are ideal toughening phases for intermetallic composites. This paper presents a novel composite having the microstructure of ductile Mo primary dendrites, binary intermetallic compound NiMo and ternary metallic silicide Mo2Ni3Si. The composite exhibits outstanding wear resistance and pretty low wear-load coefficient at ambient temperature, which are attributed to the contribution of refractory metal Mo to toughness of intermetallic matrix, in addition to the high strength and hardness of binary NiMo and ternary Mo2Ni3Si intermetallic phases. The wear mechanism analyzed by examining the worn surface and debris morphologies is in terms of soft abrasive wear.