Zhang Jianlei, Shen Guwei, Han Bingzhuo, Li Dayong, Xu Zhenyu, Chao Zhenlong, Chen Guoqin, Jiang Longtao
School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150040, China.
School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
Materials (Basel). 2024 Apr 11;17(8):1746. doi: 10.3390/ma17081746.
Retrogression and re-aging (RRA) treatment has been proven to effectively overcome the trade-off between strength and corrosion resistance. Current research focuses on the heating rate, temperature, and holding time of retrogression treatment while ignoring the retrogression cooling ways. In this paper, the effects of RRA treatment with different retrogression cooling ways on the microstructure and properties of newly developed T'/η' strengthened Al-Zn-Mg-Cu alloys were investigated by performing tests on mechanical properties, intergranular corrosion (IGC) resistance, and electrochemical corrosion behavior. The results show that the mechanical properties of samples subject to RRA treatment with water-quenching retrogression (ultimate tensile strength, yield strength, and elongation of 419.2 MPa, 370.2 MPa, and 15.9, respectively) are better than those of air-cooled and furnace-cooled samples. The corrosion resistance of water-quenching (IGC depth of 162.2 μm, corrosion current density of 0.833 × 10 A/cm) and furnace-cooled samples (IGC depth of 123.7 μm, corrosion current density of 0.712 × 10 A/cm) is better than that of air-cooled samples. Microstructure characterization reveals that the effect of the retrogression cooling rate on mechanical properties is related to the size of T'/η' precipitates with grains as well as the proportion of T' and η', while the difference in corrosion resistance depends on the continuity of grain boundary precipitates (GBPs). With mechanical properties, corrosion resistance, and time cost taken into consideration, it is appropriate to select water quenching for retrogression. These findings offer valuable insights for further design to achieve superior performance in various applications.
回归与再时效（RRA）处理已被证明能有效克服强度与耐腐蚀性之间的权衡。当前的研究集中在回归处理的加热速率、温度和保温时间上，而忽略了回归冷却方式。本文通过对力学性能、晶间腐蚀（IGC）抗性和电化学腐蚀行为进行测试，研究了不同回归冷却方式的RRA处理对新开发的T'/η'强化Al-Zn-Mg-Cu合金微观结构和性能的影响。结果表明，经水淬回归的RRA处理样品的力学性能（极限抗拉强度、屈服强度和伸长率分别为419.2 MPa、370.2 MPa和15.9）优于空冷和炉冷样品。水淬（IGC深度为162.2μm，腐蚀电流密度为0.833×10 A/cm）和炉冷样品（IGC深度为123.7μm，腐蚀电流密度为0.712×10 A/cm）的耐腐蚀性优于空冷样品。微观结构表征表明，回归冷却速率对力学性能的影响与T'/η'析出相的尺寸以及T'和η'的比例有关，而耐腐蚀性的差异取决于晶界析出物（GBP）的连续性。综合考虑力学性能、耐腐蚀性和时间成本，选择水淬进行回归是合适的。这些发现为进一步设计以在各种应用中实现卓越性能提供了有价值的见解。
