铱微柱的应变突变和应变速率敏感性  

Strain Burst and Strain Rate Sensitivity of Iridium Micropillars

作　　者：刘毅[1] 李扬 罗锡明[1] 张健康[1] 许昆[1] 李伟[1] Liu Yi;Li Yang;Luo Ximing;Zhang Jiankang;Xu Kun;Li Wei(State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metal,Kunming Institute of Precious Metals,Kunming 650106,China)

机构地区：[1]昆明贵金属研究所稀贵金属综合利用新技术国家重点实验室,云南昆明650106

出　　处：《稀有金属材料与工程》2020年第4期1200-1203,共4页Rare Metal Materials and Engineering

基　　金：Joint Funds of the National Natural Science Foundation of China(U1202273);National Natural Science Foundation of China(51501075);Special Funds of Yunnan Provincial Research Institute Technology Development(2014DC018)。

摘　　要：以聚焦离子束(FIB)制备了直径在1000 nm至7400 nm范围内的<110>取向铱单晶柱,并在纳米机械仪器Sementort中进行了单轴压缩试验。结果表明,单晶柱的屈服强度与直径有显著关系,而与FIB制备无关。单晶柱的微压缩实验与整体铱在单轴压缩试验中的力学行为不同,微纳米尺度的流动应力随着柱直径的减小而增加,即尺寸效应。此外,塑性变形过程有明显的突变和大应变,重点研究了单轴压缩下铱单晶柱的应变突变速度和应变敏感性问题。结果表明,压缩位移量随着持续时间和立柱直径的增加而增加,同时指出了应变敏感性(SRS)指数m随着柱直径的减小而增加。<110>-oriented single-crystalline iridium micropillars with diameters ranging from 1000 nm to 7400 nm were fabricated by focused-ion-beam(FIB),and uniaxial compression tests for iridium micropillars were performed using a nanomechanical instrument.The results reveal that the yield strength of micropillars follows a power law depending on diameter,as reported in other face-centered cubic(fcc)metals.Unlike the mechanical behavior of bulk iridium when uniaxial compression is performed,the micro-and nano-scale flow stress increases with decreasing the micropillar diameter,which is attributed to the size-dependent effect.Moreover,the plastic deformation shows a periodical jerky and strain bursts,and the rate of strain bursts and the sensitivity of strain rate for iridium micropillars under uniaxial compression were mainly investigated.The experiments also indicate that the displacement jump increases with increasing the duration time and micropillar diameter.In addition,the strain rate sensitivity(SRS)index m increases with decreasing the diameter of iridium micropillar.

关 键 词：铱微柱 FIB 纳米压痕 压缩试验 尺寸效应 应变突变 SRS 

分 类 号：O614.825[理学—无机化学]