层错能对面心立方金属形变机制与力学性能的影响  

Effects of Stacking Fault Energy on the Deformation Mechanisms and Mechanical Properties of Face-Centered Cubic Metals

作　　者：张哲峰[1] 李克强 蔡拓 李鹏[1] 张振军 刘睿 杨金波 张鹏[1] ZHANG Zhefeng;LI Keqiang;CAI Tuo;LI Peng;ZHANG Zhenjun;LIU Rui;YANG Jinbo;ZHANG Peng(Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所师昌绪先进材料创新中心,沈阳110016

出　　处：《金属学报》2023年第4期467-477,共11页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.52130002和51901230。

摘　　要：层错能在面心立方(fcc)金属塑性变形和损伤过程中具有重要作用,本文主要总结了以下研究结果:(1)随层错能降低,fcc金属滑移方式逐渐从易于交滑移的波状滑移方式转变为平面滑移方式,直至发生变形孪生;(2)为了理解不同位错密度fcc金属中层错能的变化趋势,采用有效层错能的概念,随位错密度增加,有效层错能也随之升高;(3)层错能降低不是决定fcc金属形变孪生发生的唯一因素,通过第一原理计算模拟滑移和孪生之间的竞争关系,建立了fcc金属形变孪生临界判据;(4)通过对高层错能、中等层错能以及低层错能fcc金属疲劳位错组态的实验观察和分析,总结了fcc金属中形成规则驻留滑移带的判定条件;(5)随Al含量增加,Cu-Al合金层错能降低导致平面滑移程度增加,其拉伸强度和均匀延伸率呈现同步提高趋势;(6)采用指数应变硬化模型可精确描述Cu-Al合金拉伸加工硬化过程,进而预测了不同合金成分和微观组织状态Cu-Al合金屈服强度-抗拉强度-均匀延伸率之间的定量关系;(7)随Al含量增加,Cu-Al合金疲劳强度升高;在相同应变幅下,随Al含量增加,其低周疲劳寿命也升高。表明合金成分明显影响fcc金属形变损伤机制及微观缺陷(位错、孪生)演变过程,进而显著影响fcc金属及合金拉伸性能和疲劳性能,这为通过合金设计和制备提高fcc金属力学性能及服役可靠性提供了实验证据和理论基础。Stacking fault energy(SFE) can play a crucial role in plastic deformation and damage mechanisms of face-centered cubic(fcc) metals.This study mainly summarized the following results:(1)With the reduction of SFE,the slip mode of fcc metals gradually changes from a facile cross-slip wavy mode to a planar mode until deformation twinning occurs;(2) The concept of effective SFE is applied to investigate the variation of SFE with dislocation density in the fcc metals,with the increase in dislocation density,the effective SFE increases;(3) The reduction of SFE is not the only factor determining the formation of deformation twins in fcc metals.In terms of calculating the competition between simulated slipping and twinning using the first principles,the critical criterion for forming deformation twinning in fcc metals was established;(4) The fatigue dislocation configuration of high-,medium-,and low-SFE fcc metals were analyzed and the judgment conditions for forming regular persistent slip bands(PSBs) are proposed;(5) With the increase in Al content,the SFE of Cu-Al alloy decreases,resulting in a simultaneous increasing trend in the tensile strength and the uniform elongation due to the increasing planar slip degree;(6) The exponential strain-hardening model can accurately describe the tensile strain-hardening process of Cu-Al alloys.The quantitative relationship among yield strength,tensile strength,and uniform elongation of Cu-Al alloy with different alloy compositions and microstructure states was successfully predicted;(7) With the increase in Al content,the fatigue strength of Cu-Al alloy is improved.Increasing Al content at the same strain amplitude will enhance its low-cycle fatigue life.Based on the experimental results above,it is shown that the alloy composition affects the deformation and damage mechanisms,and the evolution process of microscopic defects(dislocations,twins) in fcc metals and alloys.Thus,it drastically affects the tensile and fatigue properties of the fcc metals and alloys.These results provide

关 键 词：面心立方金属 层错能 滑移 孪生 强度 塑性 疲劳强度 

分 类 号：TG135[一般工业技术—材料科学与工程]