纳米压痕条件下MgB_(2)超导块材的压入力学行为研究  

Mechanical Behavior of MgB_(2) Superconducting Bulk under Nano-indentation

作　　者：王星辉 王晓严 张经斌 秦保军 赵倩 WANG Xinghui;WANG Xiaoyan;ZHANGJingbin;QIN Baojun;ZHAO Qian(China Construction Fifth Engineering Bureau Co.,LTD,Tianjin 300074,China;Tianjin Key Laboratory of Integrated Design and On-line Monitoring for Light Industry&Food Machinery and Equipment,College of Mechanical Engineering,Tianjin University of Science&Technology,Tianjin 300222,China)

机构地区：[1]中国建筑第五工程局有限公司,天津300074 [2]天津市轻工与食品工程机械装备集成设计与在线监控重点实验室,天津科技大学,机械工程学院,天津300222

出　　处：《低温物理学报》2022年第3期210-218,共9页Low Temperature Physical Letters

基　　金：国家自然科学基金资助项目(项目号:51975411)资助的课题.

摘　　要：本文采用纳米压痕技术对固相烧结法制备的MgB_(2)超导块材进行压入力学实验,对不同压深的载荷-位移曲线和纳米压痕数据的再现性进行了分析,实验数据使用Oliver-Pharr方法计算得出MgB_(2)的硬度值,借助经验方程拟合纳米压痕蠕变曲线求得蠕变速率敏感指数(m).结果表明,微观结构不均匀性会对材料在压头压入过程中抵抗外力作用时产生影响,使压痕数据再现性变差;MgB_(2)的硬度表现出尺寸效应,即随着压入深度的增加硬度逐渐下降;m值随压入深度增加而增加是位错滑移速度加快的结果.In this paper,nano indentation technology was used to conduct the mechanical experiments on MgB_(2) superconducting bulk material prepared by solid phase sintering.The reproducibility of load-displacement curves and nano-indentation data at different depths was analyzed.The hardness value of MgB_(2) was calculated by Oliver-Pharr method,and the creep rate sensitivity index(m)was obtained by fitting the creep curve of nano-indentation with empirical equation.The results show that the inhomogeneity of microstructure will affect the resistance of material to external force during the process of indenting the head,and the reproduction of the indentation data will be poor.The hardness of MgB_(2) shows size effect,that is,the hardness decreases gradually with the increase of indentation depth.The increase of m value with the increase of insertion depth is the result of the acceleration of dislocation slip velocity.

关 键 词：MgB_(2) 超导块材 纳米压痕 微观结构 硬度尺寸效应 蠕变 

分 类 号：O511.3[一般工业技术—材料科学与工程]