Investigations of annealing hardening in Au micropillar based on a modified discrete-continuous model

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• 英文论文题名：Investigations of annealing hardening in Au micropillar based on a modified discrete-continuous model
• 论文作者：Fengxian Liu ; Zhan-li Liu ; Peng Lin ; Zhuo Zhuang
• 英文论文作者：Fengxian Liu ; Zhan-li Liu ; Peng Lin ; Zhuo Zhuang ; Applied Mechanics Lab. ; School of Aerospace Engineering ; Tsinghua University
• 年：2017
• 作者机构：Applied Mechanics Lab., School of Aerospace Engineering, Tsinghua University;
• 英文论文关键词：annealing hardening ; dislocation climb ; discrete-continuous model ; jogs
• 会议召开时间：2017-01-14
• 会议录名称：北京力学会第二十三届学术年会会议论文集
• 语种：英文
• 分类号：TG156.2
• 学会代码：BJLH
• 会议名称：北京力学会第二十三届学术年会
• 会议地点：中国北京
• 主办单位：北京力学会
• 学会名称：北京力学会
• 页数：2
• 文件大小：581k
• 原文格式：D
• 会议级别：地方

摘要

In contrast to the typical behavior at macro level, recent studies at sub-micro scale have shown that metals may harden rather than soften during high temperature annealing. In the present work, a modified three-dimensional discrete-continuous mode(DCM) is proposed to address the limitations of the local model, in which the vacancy diffusion equation is solved by the FEM. Based on this DCM model, the intrinsic mechanism of annealing hardening at sub micro scale and detailed evolution of defects during the annealing are investigated. Numerical simulation results shows that the hardening is caused by the decrease of dislocation density, which can be ascribed to two main aspects:(i) The climb of dislocation during the high temperature annealing promotes the annihilation of the dislocations, leading to a decrease in dislocation density.(ii) The jogs, nucleated during annealing due to the high temperature climb, have very weak mobility and act as obstacles to the dislocation glide motion, leading to mobile dislocation starvation and resulting in a higher flow strength level.
In contrast to the typical behavior at macro level, recent studies at sub-micro scale have shown that metals may harden rather than soften during high temperature annealing. In the present work, a modified three-dimensional discrete-continuous mode(DCM) is proposed to address the limitations of the local model, in which the vacancy diffusion equation is solved by the FEM. Based on this DCM model, the intrinsic mechanism of annealing hardening at sub micro scale and detailed evolution of defects during the annealing are investigated. Numerical simulation results shows that the hardening is caused by the decrease of dislocation density, which can be ascribed to two main aspects:(i) The climb of dislocation during the high temperature annealing promotes the annihilation of the dislocations, leading to a decrease in dislocation density.(ii) The jogs, nucleated during annealing due to the high temperature climb, have very weak mobility and act as obstacles to the dislocation glide motion, leading to mobile dislocation starvation and resulting in a higher flow strength level.

引文

[1]M.G.D.Geers,M.Cottura,B.Appolaire,E.P.Busso,S.Forest,A.Villani,Coupled glide-climb diffusion-enhanced crystal plasticity,Journal of the Mechanics and Physics of Solids 70(2014)136-153.
    [2]C.Ayas,V.Deshpande,Climb Enabled Discrete Dislocation Plasticity of Superalloys,Key Engineering Materials 651-653(2015)981-986.
    [3]S.M.Keralavarma,A.A.Benzerga,High-Temperature Discrete Dislocation Plasticity,Journal of the Mechanics and Physics of Solids(2015).
    [4]Z.L.Liu,X.M.Liu,Z.Zhuang,X.C.You,A multi-scale computational model of crystal plasticity at submicron-to-nanometer scales,International Journal of Plasticity 25(8)(2009)1436-1455.
    [5]Y.Gao,Z.L.Liu,X.C.You,Z.Zhuang,A hybrid multiscale computational framework of crystal plasticity at submicron scales,Computational Materials Science 49(3)(2010)672-681.
    [6]Y.Cui,Z.Liu,Z.Zhuang,Quantitative investigations on dislocation based discrete-continuous model of crystal plasticity at submicron scale,International Journal of Plasticity 69(2015)54-72.