The comparsion of different fabrication processes on the microstructure and mechanical properties of Cu-11Al-3Ni alloy

Abstract

In this paper, two different fabrication processes, mainly including Hopkinson bar (HB) + cold rolling (CR) method (process Ⅰ) or CR + CR method (process Ⅱ), were carried out to fabricate the Cu-11Al-3Ni alloy sheet. The role of the HB method on the microstructure and mechanical properties of the Cu-11Al-3Ni alloy was investigated in detail. Due to the vast discrepancy in strain rates between the HB (102 - 103 s−1) and CR (10−2 - 10−3 s−1) processes, the fraction of twins in the HB + CR sample was attached 14.7 %, much higher than the 1.68 % of the CR + CR sample, accompanied by the increase in the frequency of recrystallised grains and the enhancement of BRASS texture component. In addition, due to the generation of fine and numerous twins and the resulting twin strengthening (σtwin), the performance of tensile strengths (including yield strength and ultimate tensile strength) in the HB + CR sample were 868 and 1051 MPa, respectively, much higher than those of the CR + CR sample (734 and 940 MPa). Consequently, the HB method was considered to be as a potential approach to obtaining ultrahigh-strength Cu alloys.