多级梯度结构对Al-Zn-Mg-Cu合金力学性能的影响  

Effect of multi-gradient structure on mechanical properties of Al-Zn-Mg-Cu alloy

作　　者：苏史航 杨明[1,2] 唐玉 杨阳 杨钢[1] 罗漂 SU Shihang;YANG Ming;TANG Yu;YANG Yang;YANG Gang;LUO Piao(School of Materials Science and Metallurgical Engineering,Guizhou University,Guiyang 550025,China;National&Local Joint Engineering Laboratory for High-performance Metal Structure Material and Advanced Manufacturing Technology,Guiyang 550025,China)

机构地区：[1]贵州大学材料与冶金学院,贵州贵阳550025 [2]高性能金属结构材料与制造技术国家−地方联合实验室,贵州贵阳550025

出　　处：《中南大学学报（自然科学版）》2023年第7期2651-2662,共12页Journal of Central South University:Science and Technology

基　　金：贵州大学大学生创新基金资助项目(2020(063))。

摘　　要：为了进一步提升析出强化铝合金的强度,采用表面超声滚压和低温时效工艺制备一种多级梯度结构材料,并用SEM/TEM表征分析表层组织。研究结果表明:表层晶粒和析出相均呈现梯度分布。此外,对梯度层的析出相分析发现晶内析出相和晶界析出相种类存在区别,并且伴随着距表面深度的增加,晶界析出相和晶内析出相的数量密度都呈现降低趋势。与时效后粗晶试样相比,多级梯度结构试样的强度得到提升(屈服强度和抗拉强度分别从480 MPa和622 MPa提升到562 MPa和692 MPa)并保持良好的塑性。通过定量计算,发现多级梯度结构试样的强化增量主要源于晶界强化、沉淀强化、位错强化和协同强化的共同作用。In order to further improve the strength of precipitation strengthened aluminum alloy,ultrasonic surface rolling process and low temperature aging were used to fabricate a multi-gradient structure.The surface deformation microstructure was characterized by SEM/TEM.The results show that the surface grains and precipitates show gradient distribution.In addition,there are differences in the types of grain boundary precipitates and grain interior precipitates with gradient structure,and the number density of grain boundary precipitates and grain interior precipitates decreases with the increase of the depth from the surface.Compared with the coarse grained sample after solution treatment,the multi-gradient structure improves the strength(yield strength and ultimate tensile strength improves from 223 MPa and 425 MPa to 562 MPa and 692 MPa,respectively)and maintains excellent plasticity.And the strengthening increment of multi-gradient structure sample is quantitatively calculated,and the high strength of multi-gradient structure originates from grain boundary strengthening,precipitation strengthening,dislocation strengthening and synergistic strengthening.

关 键 词：超声表面滚压 7075铝合金 多级梯度结构 强化机制 

分 类 号：TG132.32[一般工业技术—材料科学与工程]