The microstructure and precipitation analysis of the Cu-Ni-Fe-P alloy with high property

This article systematically investigated the aging behavior and precipitation of Cu-Ni-P, Cu-Fe-P and Cu-Ni-Fe-P alloys. The results showed that the novel quaternary Cu-Ni-Fe-P alloy designed based on ternary Cu-Ni-P alloy and ternary Cu-Fe-P alloy had the superior properties. The electrical conductivity and tensile strength reached 69.1 %IACS and 658.7 MPa, respectively, by the process (solution treatment + 30 % cold rolling reduction + pre-aging (750 °C × 1 min) + 30 % cold rolling reduction + aging (450 °C × 4 h) + 60 % cold rolling reduction + annealing (450 °C × 1 min)). The nanoscale precipitation (Ni, Fe)₂P was a hexagonal structure in Cu-Ni-Fe-P alloy. The orientation relationship between the (Ni, Fe)₂P precipitation and the matrix was [110]_Cu//[111]_{(Ni, Fe)2P}, (1-1-1)_Cu//(1–21) (_{Ni, Fe)2P}. The synergistic effect of Ni and Fe atoms facilitated the precipitation of more uniform and fine phases, effectively enhancing the overall performance of NFP alloy. The synergistic contribution of dislocation strengthening and precipitation strengthening mainly driven the yield strength of alloys and were the major strengthening mechanism. The contribution of the precipitation strengthening in NFP alloy was significantly greater than that in NP and FP alloys. That was the reason for the increased strength of NFP alloy. This work indicates that the Cu-Ni-Fe-P alloy is a promising candidate for high property Cu alloys.