Mo-Nb-W单晶微纳米力学性能的各向异性与应变速率响应特征  

Anisotropy Characteristics of Micro-and Nano-mechanical Properties and Strain Rate Response of Mo-Nb-W Single Crystal

作　　者：殷涛[1] 王宝剑 胡忠武[1] 张伟伟 白伟 任广鹏[1] 郭林江[1] 刘燕[1] 张文[1] 李建峰 Yin Tao;Wang Baojian;Hu Zhongwu;Zhang Weiwei;Bai Wei;Ren Guangpeng;Guo Linjiang;Liu Yan;Zhang Wen;Li Jianfeng(Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China)

机构地区：[1]西北有色金属研究院,陕西西安710016

出　　处：《稀有金属材料与工程》2024年第10期2897-2905,共9页Rare Metal Materials and Engineering

基　　金：工信部产业基础再造和制造业高质量发展专项(TC220H06D);西北有色金属研究院人才培养项目(0701YK2407)。

摘　　要：Mo基单晶是深空探测舰船核动力发电元件的关键材料,优化合金成分制备性能优异的单晶材料是提高核电源发电效率和服役寿命的重要途径。本研究采用电子束悬浮区域熔炼方法制备了新型Mo-Nb-W单晶,利用纳米压痕技术研究了不同取向晶面的硬度(H)、接触刚度(S)和弹性模量(E)随应变速率的变化规律。研究发现,bcc结构Mo-Nb-W单晶(111)晶面的载荷-位移曲线连续光滑变化,且塑性指数较高,表明<111>方向塑性较好,而(110)和(112)晶面的载荷-位移曲线中均出现了位移突变台阶,同时塑性指数较低,表明<110>和<112>方向塑性相对较差。随应变速率增大,3个取向晶面硬度因弛豫时间缩短而增大,而接触刚度和弹性模量有降低趋势。Mo-Nb-W单晶力学性能具有明显的各向异性,其中硬度排序为H_((111))>H_((110))>H_((112)),而接触刚度和弹性模量排序为:S_((111))>S_((112))>S_((110))和E_((111))>E_((112))>E_((110))。随压入深度增加,硬度逐渐变小,表现出明显压痕尺寸效应,其中(111)晶面尺寸效应最为明显。Mo-based single crystal is a key material for nuclear power generation components in deep space exploration ships.Optimizing alloy composition to achieve property improvement of single crystal materials is an important way to improve the power generation efficiency and service life of nuclear power sources.A novel Mo-Nb-W single crystal was prepared by electron beam suspension zone melting method,and the hardness(H),contact stiffness(S)and elastic modulus(E)of different oriented crystal planes were investigated by nanoindentation technique.The results show that there is no pop-in phenomenon in the load-displacement(P-h)curves of the(111)crystal plane,and the plasticity index is high,which indicates that the plasticity in<111>direction is good.However,the pop-in steps appear in the P-h curves of both(110)and(112)crystal planes during nanoindentation,and the plasticity index is low,indicating that the plasticity in<111>and<112>directions is relatively poor.The hardness of the measured oriented crystal planes is gradually increased with the increase in strain rate due to the shortened relaxation time,while the contact stiffness and elastic modulus are slowly decreased as strain rate increases.There is significant anisotropy in the mechanical properties of Mo-Nb-W single crystal,and the hardness is ranked as H_((111))>H_((110))>H_((112)).The order of contact stiffness and elastic modulus are as follows:S_((111))>S_((112))>S_((110))和E_((111))>E_((112))>E_((110)).The hardness of these mentioned oriented crystal planes is gradually decreased with the rise of indentation depth,and the(111)oriented crystal plane has the most obvious indentation size effect.

关 键 词：Mo基单晶 纳米压痕 各向异性 应变速率 压痕尺寸效应 

分 类 号：TG146.412[一般工业技术—材料科学与工程]