Study on substitution of Ni with Ni₃Al on structure and properties of W–6Ni₃Al–4Co alloys by two-step sintering process

Abstract

Herein, the effect of substitution of Ni with Ni 3 Al and two-step sintering on the phase transformation, microstructure evolution, and properties of W-6Ni-4Co alloys were evaluated. The results show that the reaction products of Ni 3 Al and Co include (Ni, Co) 3 Al 4 to Co 2 Al 9 during the two-step sintering process. When Ni was substituted by Ni 3 Al, the densification temperature was reduced. The distribution of W phase turned from stripes to network, and the grain size increased with an increase in the sintering temperature. The Ni 3 Al substituted sample sintered at 1500°C for 20 min displayed a combination of high densification parameter, microhardness, and strength because of denser microstructure of the alloy.