摘要
通过设计不同的表面超声滚压(USRP)参数,研究了塑性变形速率对7075-T6铝合金表面组织演化和力学性能的影响。结果表明:USRP处理可以在7075-T6铝合金表面获得不同层深的梯度纳米组织,且随着变形速率的增加表面变形层主要演化为层片状的纳米组织;当表面纳米化层趋于饱和后,最表层纳米结构片层的平均厚度约为61 nm,纳米层深度可达20μm以上;随着USRP深度的增加,纳米结构片层的宽度逐渐增大;透射电镜(TEM)分析表明表面纳米层和基体的析出相类型没有发生变化,层状纳米组织的析出相主要包含η相、η′相和GPⅡ区的混合析出物;USRP制备的梯度纳米组织提升了7075-T6铝合金的屈服强度和抗拉强度,其强化的机制与位错增殖和晶粒纳米化密切相关,且梯度纳米组织同时兼具优异的强度和塑性,层状纳米梯度组织展现出较好的应变强化能力。
Effect of plastic deformation rate on surface microstructure evolution and mechanical properties of 7075-T6 aluminum alloy was studied by designing different ultrasonic surface rolling process(USRP)parameters.The results show that USRP treatment can obtain gradient nanostructure with different layer depths on the surface of the 7075-T6 aluminum alloy,and with the increase of deformation rate,the surface deformation layer mainly evolves into layered nanostructure.When the surface nano refinement layer tends to saturate,the average thickness of the outermost nano structure layer is about 61 nm,and the depth of the nano layer can reach more than 20μm.As the depth of USRP increases,the width of the nanostructured layers gradually increases.Transmission electron microscopy(TEM)analysis results show that there is no change in the precipitation phase types of the surface nano layer and the matrix.The precipitation phases of the layered nanostructure mainly include mixed precipitates of theηphase,η′phase,and GPⅡregion.The gradient nanostructure prepared by USRP enhances the yield strength and tensile strength of the 7075-T6 aluminum alloy,and its strengthening mechanism is closely related to dislocation multiplication and grain nanocrystallization.The gradient nanostructure also has excellent strength and plasticity,and the layered nano gradient microstructure exhibits good strain strengthening ability.
作者
许发红
熊志芳
杨明
莫伟先
熊穗平
梁宇
XU Fa-hong;XIONG Zhi-fang;YANG Ming;MO Wei-xian;XIONG Sui-ping;LIANG Yu(Guizhou Special Equipment Inspection and Testing Institute,Guiyang 550014,China;School of Materials and Metallurgy,Guizhou University,Guiyang 550025,China)
出处
《材料热处理学报》
北大核心
2025年第9期172-181,共10页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(52464049)
2024年度贵州省科技成果应用及产业化(联合资金):黔科合成果-LH[2024]重大021。
关键词
7075铝合金
表面超声滚压
拉伸性能
微观组织演化
7075 aluminum alloy
ultrasonic surface rolling process
tensile property
microstructure evolution
