Study on the mechanism of microstructure and strength-ductility regulation in CuCrZr alloy via dual-gradient temperature-controlled rolling and aging treatments
Qi Li, Yahui Liu, Qianqian Zhu, Yanjun Zhou, Jiang Feng, Hailong Wang, Qingxiang Chen, Xuebin Zhang, Binbin Wang, Xiaokang Yang, Kexing Song
Abstract
Dislocations are critical to alloy strengthening but are also the dominant factor reducing electrical conductivity and ductility, making it challenging to balance these contrasting properties effectively. We innovatively introduced low-temperature factors during the rolling process to induce the formation of twins and nanotwins. These were combined with nanocrystalline grains and nanoscale precipitates to form a nanocomposite structure, thereby synergistically enhancing the alloy's strength , electrical conductivity , and ductility. The results show that the CuCrZr alloy achieves excellent comprehensive performance after processing through 85 % room-temperature rolling, aging at 420 °C for 4 h, 50 % low-temperature rolling, and a second aging treatment at 420 °C for 4 h. The alloy exhibits a tensile strength of 446 MPa, an electrical conductivity of 86 % IACS, and an elongation of 14.1 %. The dual-gradient temperature-controlled rolling and aging treatments altered the grain rotation behavior during deformation. Alloys subjected to low-temperature rolling exhibited strong Y-textures, whereas those processed through dual room-temperature rolling displayed weak Y-textures. The texture strength of the alloy processed via low-temperature rolling was higher than that of the alloy subjected to dual room-temperature rolling. The study clarified the multifactorial strengthening mechanisms and quantified the relative contributions of different factors, with grain boundary strengthening accounting for 50.5 % of the total strengthening effect .