Microstructure and dry sliding wear resistance of Moss-toughened Mo2Ni3Si metal silicide alloys

A wear resistant Mo2Ni3Si-based metal silicide alloy toughened by molybdenum-based solid solution (Moss) was fabricated by the laser melting deposition (LMD) manufacturing process. Microstructure of the alloy is composed of Moss primary dendrites and the matrix of the single phase Mo2Ni3Si. Wear resistance and friction coefficient of the alloys were evaluated under metallic dry sliding wear test conditions as a function of contact load. Results showed that the alloys have a low friction coefficient and outstanding wear resistance due to the high hardness of Mo2Ni3Si matrix and the high strength, ductility and toughness of Moss dendrites. The wear rate and the friction coefficient of alloys are extremely insensitive to the contact load owing to the abnormal hardness-temperature relation of Mo2Ni3Si. The Moss dendrite played the role of trapping micro-cracks and restraining brittle spalling of the Mo2Ni3Si matrix during wear process and improved the wear properties of Moss-toughened Mo2Ni3Si alloy.