摘要
研究了回归时效时间和回归时效温度对Al-Zn-Mg-Cu RRA合金蠕变变形和性能的影响。通过蠕变试验和单轴拉伸试验研究试样的蠕变应变和力学性能。采用涡流电导率仪测定样品的电导率,采用透射电镜(TEM)观察微组织。结果表明,随着回归时效时间的延长,蠕变应变先增大后减小,在45min时达到最大值。蠕变应变随回归时效温度的升高而增大,在200℃时达到最大。稳态蠕变应变水平由析出相和位错回复决定。蠕变时效强化了经190℃回归时效10 min的7B50-RRA合金,减小了合金力学性能差异。溶质原子的扩散减少了电子的散射,使蠕变时效大大增强了材料的导电性和抗应力腐蚀性能。研究结果有助于蠕变时效成形(CAF)技术在Al-Zn-Mg-Cu RRA合金中的应用。
A study was conducted to better understand how different parameters, namely, regression aging time and regression aging temperature, affect the creep aging properties, i.e., the creep deformation and performance of Al-Zn-MgCu alloy during regressive reaging. The corresponding creep strain and mechanical properties of samples were studied by conducting creep tests and uniaxial tensile tests. The electrical conductivity was measured using an eddy-current conductivity meter. The microstructures were observed by transmission electron microscopy(TEM). With the increase in regression aging time, the steady creep strain first increased and then decreased, and reached the maximum at 45 min.The steady creep strain increased with the increase in regression aging temperature, and reached the maximum at 200 ℃.The level of steady creep strain was determined by precipitation and dislocation recovery. Creep aging strengthens 7B50-RRA treated with regression aging time at 190 ℃ for 10 min, and the difference in the mechanical properties of alloy becomes smaller. The diffusion of solute atoms reduces the scattering of electrons, leading to a significant improvement in electrical conductivity and stress corrosion cracking(SCC) resistance after creep aging. The findings of this study could help in the application of creep aging forming(CAF) technology in Al-Zn-Mg-Cu alloy under RRA treatment.
作者
彭南辉
湛利华
马博林
王庆
徐凌志
余汶芳
沈烽
PENG Nan-hui;ZHAN Li-hua;MA Bo-lin;WANG Qing;XU Ling-zhi;YUWen-fang;SHEN Feng(School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;Light Alloy Research Institute,Central South University,Changsha 410083,China;State Key Laboratory of High-Performance Complex Manufacturing,Central South University,Changsha 410083,China;Zte Corporation,Changsha 410205,China;Shanghai Institute of Spaceflight Control Technology,Shanghai 201109,China)
基金
Project(2017YFB0306300) supported by the National key R&D Program of China
Projects(51675538, 51905551)supported by the National Natural Science Foundation of China
Project(ZZYJKT2019-11) supported by Free Exploration Project of State Key Laboratory of High performance Complex Manufacturing,China。
