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

A wear resistant Mo₂Ni₃Si-based metal silicide alloy toughened by molybdenum-based solid solution (Mo_ss) was fabricated by the laser melting deposition (LMD) manufacturing process. Microstructure of the alloy is composed of Mo_ss 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 Mo_ss 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 Mo_ss 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 Mo_ss-toughened Mo₂Ni₃Si alloy.