Disintegration of the net-shaped grain-boundary phase by multi-directional forging and its influence on the microstructure and properties of Cu–Ni–Si alloy

Cu–Ni–Si alloys with 90% Cu content and Ni to Si ratios of 5:1 were fabricated by fusion casting, and severe plastic deformation of the Cu–Ni–Si alloy was carried out by multi-direction forging (MDF). The results showed that the as-cast and homogenized Cu–Ni–Si alloys consisted of three phases, namely the matrix phase α -Cu (Ni, Si), the reticular grain boundary phase Ni₃₁Si₁₂ and the precipitated phase Ni₂Si. MDF significantly destroyed the net-shaped grain boundary phase, the Ni₃₁Si₁₂ phase and refined the grain size of the Cu matrix, and also resulted in the dissolving of Ni₂Si precipitates into the Cu matrix. The effect of MDF on the conductivity of the solid solution Cu–Ni–Si alloy was very significant, with an average increase of 165.16%, and the hardness of the Cu–Ni–Si alloy also increased obviously. (paper)