Effect of Si on Mechanical Properties and Microstructures of Ni-B-Si-WC-Mo Alloys

Abstract

The effects of Si contents on the mechanical properties and microstructures of Ni-2.2 mass%B-(0-6.4)mass%Si-30mass%WC-15mass%Mo alloys were studied. The transverse-rupture strength ( TRS ) declined as the Si contents increased after the TRS reached its peak (2.0GPa) at 3.2 mass% Si. The TRS values of the alloys increased with dissolution of Si into binder phase and with dispersion of fine Ni₃Si particles. In the case of coarse Ni₃Si, Ni₃₁Si₁₂ particles were formed in the binder phase, the TRS decreased.
The hardness increased as Ni₃Si, Ni₃₁Si₁₂ was formed in the binder phase. The maximum hardness of HRA87.5 was obtained at 6.4 mass% Si.