Microstructure evolution and strengthening mechanism of Cu_x[Ni₃Mo] alloys

Abstract

Mo could be dissolved into Cu to increase its high-temperature stability via a Ni intermediate. The microstructure evolution and strengthening mechanism of Cu x[Ni3Mo] ( x = 1, 2, 3, 4, 5, 7, 9, 12) alloys were investigated. The results show that composition significantly affects strengthening mechanisms of the alloys. For x = 1 and 2, The strengthening mechanisms of the alloys are mainly precipitation strengthening derived from Ni2Mo and Ni4Mo nanophases, both of which coexist and coherently grow on the face-centered cubic matrix. For x = 3–5, the nanophases gradually decrease and spinodal decomposition structure increases, which transforms the strengthening mechanism to spinodal decomposition strengthening. For x = 7–12, spinodal decomposition structure and precipitates reduce significantly, the solution strengthening dominates namely.