In recent years, Cu has been regarded as an important element to improve the corrosion resistance of stainless steels. For duplex stainless steels, especially those obtained by cold rolling and annealing, at present, little is known about the role mechanism of Cu addition. Therefore, on the basis of a new type of Fe–Cr–Mn–Al duplex stainless steel designed by the author, the effects of Cu on phase fraction, mechanical properties and corrosion resistance were studied in detail through tensile tests, electron backscattering diffraction (EBSD), polarization curve test and laser scanning confocal microscopy. The results show that the addition of 0.5% Cu to Fe–Cr–Mn–Al system increases the volume fraction of austenite and its stability, greatly improving the strength and ductility of steels due to the TRIP effect occurring in a wider strain range. In addition, the addition of Cu increases the content of Cr in austenite, improving the pitting resistance of duplex stainless steels. After annealing at 860 °C, the Cu-added duplex stainless steel exhibits superior mechanical and corrosive properties, i.e. the yield strength, tensile strength, elongation and pitting potential are 520 MPa, 760 MPa, 42.5% and 260 mV, respectively. In view of obvious advantages in mechanical properties and corrosion resistance, the present developed Cu-added Fe–Cr–Mn–Al duplex stainless steel is expected to replace the conventional 304 stainless steel for some applications.

近年来，Cu被认为是提高不锈钢耐蚀性的重要元素。对于双相不锈钢，尤其是冷轧和退火得到的双相不锈钢，目前对添加Cu的作用机制知之甚少。因此，在笔者设计的新型Fe-Cr-Mn-Al双相不锈钢的基础上，通过拉伸试验、电子背散射衍射（ EBSD)、偏振曲线测试和激光扫描共聚焦显微镜。结果表明，在 Fe-Cr-Mn-Al 体系中添加 0.5% Cu 增加了奥氏体的体积分数及其稳定性，由于在更宽的应变范围内发生的 TRIP 效应，大大提高了钢的强度和延展性。另外，Cu的加入提高了奥氏体中Cr的含量，提高了双相不锈钢的耐点蚀性。经860℃退火后，加铜双相不锈钢表现出优异的机械性能和腐蚀性能，即屈服强度、抗拉强度、延伸率和点蚀电位分别为520 MPa、760 MPa、42.5%和260 mV。鉴于在机械性能和耐腐蚀性能方面的明显优势，目前开发的加铜Fe-Cr-Mn-Al双相不锈钢有望在某些应用领域替代传统的304不锈钢。即屈服强度、抗拉强度、伸长率和点蚀电位分别为520 MPa、760 MPa、42.5%和260 mV。鉴于在机械性能和耐腐蚀性能方面的明显优势，目前开发的加铜Fe-Cr-Mn-Al双相不锈钢有望在某些应用领域替代传统的304不锈钢。即屈服强度、抗拉强度、伸长率和点蚀电位分别为520 MPa、760 MPa、42.5%和260 mV。鉴于在机械性能和耐腐蚀性能方面的明显优势，目前开发的加铜Fe-Cr-Mn-Al双相不锈钢有望在某些应用领域替代传统的304不锈钢。