高熵碳化物陶瓷及其钎焊接头的组织和力学性能  

Microstructures and Mechanical Properties of High-entropy Carbide Ceramics and Its Brazed Joints

作　　者：王颖[1,2] 木瑞洁 牛士玉 孙孔波 杨振文[1,2] WANG Ying;MU Ruijie;NIU Shiyu;SUN Kongbo;YANG Zhenwen(Tianjin Key Lab of Advanced Joining Technology,Tianjin University,Tianjin 300350;Key Laboratory of Advanced Ceramics and Machining Technology of Ministry of Education,Tianjin University,Tianjin 300350)

机构地区：[1]天津大学天津市现代连接技术重点实验室,天津300350 [2]天津大学先进陶瓷与加工技术教育部重点实验室,天津300350

出　　处：《机械工程学报》2024年第22期76-85,共10页Journal of Mechanical Engineering

基　　金：国家自然科学基金优秀青年(52222511)和国家自然科学基金面上(52175357)资助项目。

摘　　要：为了实现高熵碳化物陶瓷(High-entropy carbide ceramics,HECs)的大尺寸和复杂形状成形,通过热压烧结成功制备了七种不同组分的HECs,烧结的HECs均为单一岩盐结构的固溶体相,其中,(TiZrHfNbTa)C和(VNbTaMoW)C具有较高的弯曲强度,分别为494 MPa和476 MPa,且(TiZrHfNbTa)C的硬度高于(VNbTaMoW)C。在此基础上,以(TiZrHfNbTa)C为基体,采用TiNi-20at.%Nb合金和FeCoCrNiTi0.2高熵合金(High-entropy alloy,HEA)钎料制备了冶金结合良好的HEC接头。两种液态钎料中的活性Ti元素在HEC表面富集并诱导界面反应,这一过程导致界面的(Ti,Nb)C相和碳化物相(HEC')分别在HEC/TiNiNb/HEC接头和HEC/HEA/HEC接头中形成,由此产生的界面结构分别为HEC/(Ti,Nb)C/(Ti,Nb)2Ni/TiNi/(Ti,Nb)2Ni/(Ti,Nb)C/HEC和HEC/HEC'/HEA'/HEC'/HEC。在1 180℃-10 min的钎焊工艺参数下获得的HEC/TiNiNb/HEC接头具有201 MPa的抗剪强度。接头薄弱区为(Ti,Nb)2Ni相及其与(Ti,Nb)C层的界面。与之相比,HEC/HEA/HEC接头表现出更高的抗剪强度(>245 MPa),但其钎焊工艺要求更高的温度(1 400~1 490℃)和更长的时间(30 min)。To realize large-sized and complex-shaped forming of high-entropy carbide ceramics(HECs),seven HECs with different compositions are successfully prepared by hot-pressing sintering,and the sintered HECs are all solid-solution phases with single rock salt structures.Among which,(TiZrHfNbTa)C and(VNbTaMoW)C possesses the higher bending strengths of 494 MPa and 476 MPa,respectively,and the hardness of(TiZrHfNbTa)C is higher than that of(VNbTaMoW)C.On this basis,by selecting(TiZrHfNbTa)C as the substrate,HEC joints with good metallurgical bonding are prepared employing TiNi-20at.%Nb alloy and FeCoCrNiTi0.2 high-entropy alloy(HEA)fillers.Active Ti atoms in the two liquid fillers are enriched on the HEC surface and induced interfacial reaction,which led to the formation of interfacial(Ti,Nb)C phase and high-entropy carbide phase(HEC').The resulting interfacial structures of the HEC/TiNiNb/HEC joint and the HEC/HEA/HEC joint are HEC/(Ti,Nb)C/(Ti,Nb)2Ni/TiNi/(Ti,Nb)2Ni/(Ti,Nb)C/HEC and HEC/HEC'/HEA'/HEC'/HEC,respectively.The HEC/TiNiNb/HEC joint obtaind at the brazing process of 1180℃-10 min had the shear strength of 201 MPa.The weak zone of the joint is the(Ti,Nb)2Ni phase and its interface with the(Ti,Nb)C layer.In comparison,the HEC/HEA/HEC joint showes a higher shear strength(>245 MPa),while its brazing process required the higher temperatures(1400-1490℃)and longer time(30 min).

关 键 词：高熵碳化物陶瓷 热压烧结 钎焊接头 界面结构 力学性能 

分 类 号：TG156[金属学及工艺—热处理]