铌/硅化物原位自生复合材料微米棒状向纳米层片状共晶组织转变及其硬化行为  

Transition from micro-rod to nano-lamella eutectics and its hardening effect in niobium/silicide in-situ composites

作　　者：郭跃岭 张思源 何骏阳 逯文君 贾丽娜[2] 李志明 张虎[2] Yue-ling GUO;Si-yuan ZHANG;Jun-yang HE;Wen-jun LU;Li-na JIA;Zhi-ming LI;Hu ZHANG(School of Mechanical Engineering,Beijing Institute of Technology,Beijing 100081,China;Frontier Institute of Science and Technology Innovation,Beihang University,Beijing 100191,China;Max-Planck-Institut für Eisenforschung,Max-Planck-Straße 1,Düsseldorf,40237,Germany)

机构地区：[1]北京理工大学机械与车辆学院,北京100081 [2]北京航空航天大学前沿科学技术创新研究院,北京100191 [3]Max-Planck-Institut für Eisenforschung,Max-Planck-Straße 1,Düsseldorf,40237,Germany

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第8期2406-2416,共11页中国有色金属学报（英文版）

基　　金：the financial support from China Postdoctoral Science Foundation(No.2021M690384);the National Natural Science Foundation of China(No.51571004)。

摘　　要：以Nb−18Si(摩尔分数,%)复合材料为研究对象,分析共晶组织几何形态对电子束表面熔化(EBSM)快速凝固条件的响应机理及其对材料硬度的影响规律。研究结果表明,Nbss/Nb3Si共晶在电弧熔炼凝固条件下以棒状形态为主,而在EBSM凝固条件下转变为层片状形态。利用原子尺度的扫描透射电子显微镜(STEM)和近原子尺度的三维原子探针(APT)对样品进行表征,获得纳米Nbss/Nb_(3)Si共晶的三维层片状结构特征及其组分。与棒状共晶相比,EBSM凝固条件下形成的层片状共晶组织显著细化(共晶间距为39.5 nm),Nbss相体积分数大幅增加(约41%)。随着显微组织由微米棒状共晶转变为纳米层片状共晶,材料硬度显著增加,达到13.9 GPa。To improve the mechanical properties of niobium/silicide in-situ composites via rapid solidification,the evolution of eutectic geometry and the corresponding hardening effect in a prototype Nb−18Si(at.%)composite upon electron beam surface melting(EBSM),i.e.,a rapid remelting and solidifying sequence,were studied.Results show that rod-like Nb solid solution(Nbss)/Nb_(3)Si eutectics prevail in the arc-melted state,yet evolve into lamellar arrangements after EBSM.Atomic scale scanning transmission electron microscopy(STEM)and near-atomic scale atom probe tomography(APT)were employed to characterize the three-dimensional stacking of nano-laminated Nbss/Nb_(3)Si eutectics and their compositions.Compared with the rod-like eutectics,the lamellar eutectics via EBSM demonstrate a prominent eutectic refinement(39.5 nm in spacing)and an increased volume fraction of Nbss(~41%).Nano-indentation testing reveals that with the microstructural transition from micro-rod to nano-lamella eutectics,a significant increment in hardness up to 13.9 GPa is achieved.

关 键 词：铌/硅化物复合材料 快速凝固 共晶形态 层片状共晶 棒状共晶 

分 类 号：TB333[一般工业技术—材料科学与工程]