Ni-Cr钎料钎焊金刚石界面强化的第一性原理计算与试验研究  

First-principles Calculations and Experimental Study on Interface Strengthening of Brazed Diamond with Ni-Cr Filler

作　　者：张健[1] 肖昂 张澳 刘俊艺 张明军[1] 彭平[2] ZHANG Jian;XIAO Ang;ZHANG Ao;LIU Junyi;ZHANG Mingjun;PENG Ping(Hunan Provincial Key Laboratory of Intelligent Manufacturing Technology for High-performance Mechanical Equipment,Changsha University of Science and Technology,Changsha 410114;College of Materials Science and Engineering,Hunan University,Changsha 410082)

机构地区：[1]长沙理工大学机械装备高性能智能制造湖南省重点实验室,长沙410114 [2]湖南大学材料科学与工程学院,长沙410082

出　　处：《机械工程学报》2023年第18期228-238,共11页Journal of Mechanical Engineering

基　　金：湖南省自然科学基金(2023JJ30046);长沙市科技计划(kq1907089)资助项目

摘　　要：采用第一性原理计算方法,系统研究强碳化物形成元素X(X=Mn、Ti、V、Zr、Nb、Mo、Hf、Ta、W)掺杂的Ni-Cr钎料钎焊金刚石界面微观作用行为及机理,并通过钎焊金刚石试验对计算结果进行验证。嵌入能、界面分离功及界面能的计算结果表明,强碳化物形成元素X均倾向于在Ni-Cr钎料与金刚石的界面处偏析,并且不同程度地增强Ni-Cr钎料与金刚石的界面结合强度与稳定性,其中,Hf、Ta、Zr、Nb、W的强化效果尤为明显;电子结构分析表明,强碳化物形成元素X的掺杂可促进Ni-Cr钎料中的Cr原子与金刚石中的C原子成键,有效改善Ni-Cr钎料对金刚石的润湿性,同时还削弱Ni元素对金刚石石墨化的催化作用。基于Nb掺杂Ni-Cr钎料的钎焊金刚石试验表明,Nb掺杂使得Ni-Cr钎料对金刚石的爬升效果更为明显,界面冶金反应更为充分,金刚石表面生成Cr3C2和Cr7C3两种碳化物,界面得到有效强化;同时,Nb掺杂还明显削弱Ni元素对金刚石的石墨化催化作用,进而提高钎焊金刚石试件的加工性能,很好地验证理论计算结果。研究工作为基于材料基因组理念的钎焊金刚石钎料设计开发提供理论依据与参考。The micro-behavior and mechanism of brazed diamond with Ni-Cr filler doped with strong carbide-forming elements X(X=Mn,Ti,V,Zr,Nb,Mo,Hf,Ta,W)were systematically studied through first-principles calculations method,and the obtained results were verified by brazing diamond experiments.The calculation results of insertion energy,interfacial separation work and interface energy show that the strong carbide-forming element X tends to segregate at the interface between Ni-Cr filler and diamond,and the bonding strength and stability of interface between Ni-Cr filler and diamond are enhanced to varying degrees.Among them,Hf,Ta,Zr,Nb and W have the most obvious strengthening effect.Electron structure analyses show that the bonding between Cr atom in Ni-Cr filler and C atom in diamond can be promoted by doping X.The wettability of Ni-Cr filler to diamond is improved effectively,and the catalytic effect of Ni on diamond graphitization is weakened.Brazing diamond experiments based on Nb-doped Ni-Cr filler show that Nb doping makes the climbing effect of Ni-Cr filler on diamond more obvious,and the interfacial metallurgical reaction is more sufficient.Two kinds of carbides Cr3C2 and Cr7C3 are formed on the diamond surface,which effectively strengthens the interface between filler and diamond.Meanwhile,Nb doping also significantly weakens the catalytic effect of Ni element on diamond graphitization.Thus,the processing performance of brazed diamond specimen is improved,which verifies the theoretical calculation results.The obtained results provide the theoretical basis and reference for the design and development of filler alloy of brazing diamond based on material genome concept.

关 键 词：钎焊金刚石 Ni-Cr钎料 界面强化 强碳化物形成元素 第一性原理计算 

分 类 号：TG454[金属学及工艺—焊接]