张文,张平祥,高选乔,李来平,胡忠武,程军,赵彬.不同晶体取向Mo-Nb单晶的纳米压痕尺寸效应[J].稀有金属材料与工程,2018,47(3):822~828.[ZhangWen,ZhangPingxiang,GaoXuanqiao,LiLaiping,HuZhongwu,ChengJun,ZhaoBin.Indentation Size Effect in Molybdenum-Niobium Single Crystals of Different Crystallographic Orientations[J].Rare Metal Materials and Engineering,2018,47(3):822~828.]
不同晶体取向Mo-Nb单晶的纳米压痕尺寸效应
投稿时间:2017-10-23  修订日期:2017-10-31
中文关键词:  钼铌单晶  纳米压痕  纳米硬度  弹性模量
基金项目:
中文摘要:
      采用纳米压痕仪和扫描探针显微镜对Mo-Nb合金单晶(110)、(111)、(112)晶面的载荷-位移曲线、压痕形貌、纳米硬度-加载深度以及弹性回复率的变化进行了研究。结果表明,Mo-Nb单晶具有较好的塑性变形能力,Mo-Nb单晶的各晶面在加载和卸载过程中分别经历了弹性变形和塑性变形阶段,荷载-位移曲线未出现突进或突退现象,表明在加载和卸载过程中压痕内部未产生裂纹或脆性断裂;材料的残余压痕呈现凸起形貌,表明Mo-Nb单晶有相对较低的加工应变硬化趋势;采用连续刚度法测量了Mo-Nb单晶的纳米硬度和弹性模量,三个晶面的纳米硬度均呈现出随着加载深度的增加而减小的趋势,表现出明显的压痕尺寸效应;三个晶面纳米硬度和弹性模量的大小关系为: (110)晶面>(112)晶面>(111)晶面;基于Nix-Gao模型计算了(110)、(111)、(112)晶面的无压痕尺寸效应时的纳米硬度(H_0)分别为3.96GPa、2.61Gpa和3.47GPa,尺寸效应因子(i)分别为0.18、0.16和0.18,微观特征长度(h^*)分别为1196nm、2753nm和1559nm。压入深度小于微观特征长度时,Mo-Nb单晶具有明显的尺寸效应,压入深度超过该长度时,尺寸效应将减弱,当压入深度分别超过4106nm、5645nm和4693nm时,纳米压痕尺寸效应将消失。
Indentation Size Effect in Molybdenum-Niobium Single Crystals of Different Crystallographic Orientations
英文关键词:Molybdenum-Niobium single crystals  Nanoindentation  Nanohardness  Elastic modulus
英文摘要:
      The load-displacement curves, elastic modulus, indent morphology, nanohardness and elastic recovery of high purity Molybdenum-Niobium single crystal were investigated by nanoindentation and scanning probe microscopy. The results show that Mo - Nb single crystal has a good plastic deformation ability. Mo-Nb crystal plane undergo elastic deformation and plastic deformation during the loading-unloading process, and the load-displacement curve do not show discontinuity, which demonstrates that cracks and brittle fracture are not formed in the indents. Moreover, the pile-up behavior around indents reveals that Mo-Nb single crystal has the low work hardening tend. The nanohardness and elastic modulus of Mo-Nb single crystal were measured by continuous stiffness measurement (CSM), and a size effect on the nanohardness and elastic modulus was observed, which decrease with the increase of indentation depth. The relationship the different nanohardness and elastic modulus is: (110) crystal plane > (112) crystal plane > (111) crystal plane. The Nix-Gao model was employed to analyze the nanoindentation mechanical characteristics of Mo-Nb single crystal, and the intrinsic hardness in the limit of infinite depth (H_0) are 3.96GPa, 2.61GPa and 3.47GPa, respectively; the size effect index(i) were calculated to be 0.18, 0.16 and 0.18, respectively. The characteristic length(h^*) of (110), (111), (112) crystal plane are 1196 nm, 2753nm and 1559 nm, respectively. Mo-Nb single crystal has a significant size effect when the indentation depth is below the characteristic length, and the size effect becomes more insignificant when indentation depth is deeper than the characteristic length. The nanoindentation size effect will disappear as the impression are deeper than 4106nm、5645nm和4693nm, respectively.
作者单位E-mail
张文 西北工业大学 zhangw@mail.nwpu.edu.cn 
张平祥 西北有色金属研究院  
高选乔 西北有色金属研究院  
李来平 西北有色金属研究院  
胡忠武 西北有色金属研究院  
程军 西北有色金属研究院  
赵彬 西北有色金属研究院  
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