The Portevin-Le Chatelier effect of gradient nanostructured 5182 aluminum alloy by surface mechanical attrition treatment
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2018年第12期
论文作者：Xiangchen Meng Bei Liu Lan Luo Yan Ding Xi-Xin Rao Bin Hu Yong Liu Jian Lu
文章页码：2307 - 2315
摘 要：Nanocrystalline surface layers and gradient nanostructure in 5182 aluminum alloy have been produced through surface mechanical attrition treatment（SMAT）. The results indicate that the gradient nanostructure can not only improve the mechanical properties of 5182 Al alloy, but also has a certain effect on the Portevin-Le Chatelier（PLC） effect. The yield and ultimate tensile strength of 5182 Al alloy with SMAT are significantly improved combining with the decrease of fracture elongation compared with the as-received one. The PLC effect of 5182 Al alloy could be effectively postponed by the formation of gradient nanostructure after SMAT. It leads to the increase of critical strain of the PLC effect, more concentrated distribution of serrated strain, and increase of average stress amplitude in special strain range. The influence of grain size and gradient nanostructure on the PLC effect of 5182 Al alloy was also discussed in detail. Grain refinement could sharply increase the density of dislocations and hinder the movement of dislocations, which results in the decrease of moving speed of dislocations and the more concentrated distribution of solute atoms. The solute atoms would aggregate to form nano precipitates and further impede movement of dislocation. The stronger interaction between the dislocations and the nano precipitates is the main mechanism of postponed PLC effect.
Xiangchen Meng1，Bei Liu1，Lan Luo1,2，Yan Ding1,2，Xi-Xin Rao1，Bin Hu3，Yong Liu1，Jian Lu4,5
1. Key Laboratory of Lightweight and High Strength Structural Materials of Jiangxi Province,Nanchang University2. School of Materials Science & Engineering,Nanchang University3. China Science Lab.,General Motors Research & Development4. Department of Mechanical and Biomedical Engineering,City University of Hong Kong5. Centre for Advanced Structural Materials,City University of Hong Kong,Shenzhen Research Institute
摘 要：Nanocrystalline surface layers and gradient nanostructure in 5182 aluminum alloy have been produced through surface mechanical attrition treatment（SMAT）. The results indicate that the gradient nanostructure can not only improve the mechanical properties of 5182 Al alloy, but also has a certain effect on the Portevin-Le Chatelier（PLC） effect. The yield and ultimate tensile strength of 5182 Al alloy with SMAT are significantly improved combining with the decrease of fracture elongation compared with the as-received one. The PLC effect of 5182 Al alloy could be effectively postponed by the formation of gradient nanostructure after SMAT. It leads to the increase of critical strain of the PLC effect, more concentrated distribution of serrated strain, and increase of average stress amplitude in special strain range. The influence of grain size and gradient nanostructure on the PLC effect of 5182 Al alloy was also discussed in detail. Grain refinement could sharply increase the density of dislocations and hinder the movement of dislocations, which results in the decrease of moving speed of dislocations and the more concentrated distribution of solute atoms. The solute atoms would aggregate to form nano precipitates and further impede movement of dislocation. The stronger interaction between the dislocations and the nano precipitates is the main mechanism of postponed PLC effect.
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