Tension and compression creep aging asymmetry of a pre-treated Al-Zn-Mg-Cu alloy  

预处理Al-Zn-Mg-Cu合金的拉压蠕变时效不对称性

作　　者：LAO Shan-feng XU Ke-ren WANG Tao ZHAN Li-hua XU Yong-qian HUANG Ming-hui MA Bo-lin YANG You-liang GUO Wen-xing 劳山峰;许可人;王涛;湛利华;徐永谦;黄明辉;马博林;杨有良;郭文星(School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China;State Key Laboratory of High-performance Complex Manufacturing,Central South University,Changsha 410083,China;Capital Aerospace Machinery Corporation,Beijing 100076,China;Jiujiang Vocational and Technical College,Jiujiang 332000,China;Shanghai Spaceflight Precision Machinery Institute,Shanghai 201600,China)

机构地区：[1]School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China [2]State Key Laboratory of High-performance Complex Manufacturing,Central South University,Changsha 410083,China [3]Capital Aerospace Machinery Corporation,Beijing 100076,China [4]Jiujiang Vocational and Technical College,Jiujiang 332000,China [5]Shanghai Spaceflight Precision Machinery Institute,Shanghai 201600,China

出　　处：《Journal of Central South University》2025年第1期1-20,共20页中南大学学报(英文版)

基　　金：Project(2021YFB3400900)supported by the National Key R&D Program of China;Projects(51905551,52205435)supported by the National Natural Science Foundation of China Youth Foundation;Project(2022ZZTS0196)supported by the Fundamental Research Founds for the Central Universities,China;Project(CX20220282)supported by the Hunan Provincial Innovation Foundation for Postgraduate,China。

摘　　要：The asymmetric creep aging behaviors of a pre-treated Al-Zn-Mg-Cu alloy under high and low stresses have been investigated for high precision creep age forming application of aluminum integral panels.With the increase of applied stress,the creep strains under the tensile stresses are higher than those of compressive stresses and the asymmetry of creep strain is more obvious.However,the mechanical properties of tensile stress creep aged samples are lower than those of compressive stress creep aged samples.Dislocation density,dislocation moving velocity and the proportion of precipitates directly lead to the asymmetry of creep strain and mechanical properties after tensile-compressive creep aging process.In addition,the tensile and compressive stresses have little effect on the width of the precipitate-free zone(PFZ).It indicates that in the high stress creep age forming process of the pretreated Al-Zn-Mg-Cu alloy,the tensile stress promotes the dislocation motion to obtain a better creep strain but weakens its mechanical properties compared with the compressive stress.In the field of civil aviation aircraft component manufacturing,the introduction of tension and compression stress asymmetry into the creep constitutive model may improve the accuracy of creep age forming components.针对铝合金整体壁板的高精度蠕变时效成形应用,研究了预处理Al-Zn-Mg-Cu合金在高、低应力下的非对称蠕变时效行为。随着外加应力的增大,拉应力作用下的蠕变应变大于压应力作用下的蠕变应变,且拉压蠕变应变的不对称性更加明显。然而,拉应力蠕变时效后试样的力学性能均低于压应力蠕变时效的。拉伸蠕变时效过程的位错运动比压缩蠕变时效过程更剧烈,当外加应力小于250 MPa时则相反。位错密度、位错运动速度以及η'相和GPZ的比例直接导致了拉伸-压缩蠕变时效后蠕变应变和力学性能的不对称性。此外,拉伸和压缩应力对无沉淀析出带的宽度影响不大,但拉伸蠕变时效后晶界析出相的不连续性更加明显。这表明,对预处理后的Al-Zn-Mg-Cu合金进行高应力蠕变时效成形时,应考虑非对称蠕变时效行为对成形精度影响。若在民航飞行器构件制造领域中将拉压应力不对称性因素引入蠕变本构模型可提高蠕变时效成形构件的精度。

关 键 词：Al-Zn-Mg-Cu alloy mechanical properties creep ageing tension and compression asymmetry dislocation density 

分 类 号：TG1[金属学及工艺—金属学]