Study of the mechanical, structural, and electrical properties and annealing effect of a Cu–30Zn–1Ni–0.2Si alloy fabricated using cryogenic rolling

In the present study, the Cu–30Zn alloy was selected as the experimental material, the Ni and Si elements were added to prepare a new Cu–30Zn–1Ni–0.2Si alloy. The two alloys subjected to cryogenic rolling were annealed at 300 °C for different times. Their mechanical, structural, and electrical properties have been characterized. The results revealed that the strength of Cu–30Zn alloy decreases severely after annealing, but the Cu–30Zn–1Ni–0.2Si alloy maintains a high strength due to the generation of Ni₂Si precipitates. For example, the average tensile strength of the as–rolled Cu–30Zn alloy is 711.3 MPa, while it reduces to 562.3 MPa and 546.7 MPa after annealing for 1 h and 2 h. In contrast, the average tensile strength of the as–rolled Cu–30Zn–1Ni–0.2Si alloy is 742.5 MPa, it can be enhanced to 768.4 MPa when annealing at 300 °C for 1 h. Moreover, even prolonging the annealing time to 2 h, the average strength is still 701.3 MPa which is close to that of the as–rolled Cu–30Zn alloy. This study provided a feasible strategy to solve the exclusion of strength and ductility in the Cu–30Zn alloy fabricated through cryogenic rolling followed by annealing, and it may also be suitable for other Cu–Zn alloys and solid solution strengthening alloys. (paper)