Study on the Microstructure and Properties of Cu-1.5Ni-0.32P Alloy

Abstract

This study investigated the Cu-1.5Ni-0.32P alloy processed via hot rolling, solution treatment, cold rolling, and aging, focusing on the influence of cold rolling deformation degree and aging parameters on its microstructure and properties. The results show that the properties of as-cast Cu-1.5Ni-0.32P alloy are uneven due to the enrichment of coarse Ni-P second phase at grain boundaries. After hot rolling with 50% deformation at 900 °C for 2 h and solid solution treatment at 900 °C for 1 h, the second phase is completely dissolved and fine equiaxed grains are formed. The hardness is increased to 125.6 HV, but the conductivity is reduced to 30.1% IACS. After further optimization by 75% cold rolling and aging, it is found that spherical nano-Ni₃P phase precipitates after aging at 450 °C for 6 h, the hardness reaches a peak of 210.7 HV, and the conductivity increases to 65.8% IACS, representing a 138% increase in hardness and a 51% increase in electrical conductivity compared to the as-cast alloy. In this state, the alloy maintains high electrical conductivity while achieving a significant increase in strength, demonstrating outstanding combined properties of high strength and high conductivity. When the aging time was prolonged to 9 h, it was transformed into rod-like Ni₂P phase, which was coherent with the Cu matrix, and the texture was transformed from {001} < 100 > Cube to {112} < 111 > Copper. This study provides important reference for achieving synergistic enhancement of strength and electrical conductivity in Cu-Ni-P alloys through optimized process routes.