激光选区熔化NbMoTaW系难熔高熵合金组织韧化与性能研究(特邀)  

Microstructure Toughening and Properties of Selective Laser Melted NbMoTaW Refractory High⁃Entropy Alloys(Invited)

作　　者：徐金涛 周庆军 严振宇 李东来 杜尚哲 段然 孙军浩 冯凯[1] 李铸国[1] Xu Jintao;Zhou Qingjun;Yan Zhenyu;Li Donglai;Du Shangzhe;Duan Ran;Sun Junhao;Feng Kai;Li Zhuguo(School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Capital Aerospace Machinery Co.,Ltd.,Beijing 100076,China;SJTUYibin Innovation Center for Advanced Materials,Yibin 644000,Sichuan,China)

机构地区：[1]上海交通大学材料科学与工程学院,上海200240 [2]首都航天机械有限公司,北京100076 [3]宜宾上交大新材料研究中心,四川宜宾644000

出　　处：《中国激光》2024年第10期152-162,共11页Chinese Journal of Lasers

摘　　要：NbMoTaW难熔高熵合金(RHEA)在超高温下表现出优异的力学性能,但其室温脆性限制了其在航空航天等领域中的应用。采用激光选区熔化技术制备了(NbMoTaW)100-xCx和NbMoTaWTix两种难熔高熵合金(x%为原子数分数),通过合金化的方法提高了NbMoTaW合金的室温脆性抗性。研究表明:原子数分数为0.5%的C的加入显著提高了NbMoTaW合金的成形性和室温力学性能,使(NbMoTaW)99.5C0.5合金的屈服强度、极限抗压强度和塑性分别提高到1695 MPa、1751 MPa和6.9%;随着Ti含量的增加,NbMoTaWTix合金的强度和塑性也同时提高。研究结果为增材制造高强韧的NbMoTaW系难熔高熵合金提供了一种新的研究思路。Objective NbMoTaW refractory highentropy alloy(RHEA)exhibits excellent mechanical properties at ultrahigh temperatures,making it especially suitable for hightemperature heatresistant loadbearing component applications;however,its room temperature brittleness limits its application in aerospace and other fields.Moreover,the high hardness and brittleness of RHEA at room temperature make it extremely difficult to process,and hence the formation of precision and complex parts of RHEA is particularly difficult,further limiting its application.Therefore,improving the formation and plasticity of NbMoTaW RHEA is an important research topic.Methods In this study,two RHEAs,NbMoTaW100-xCx and NbMoTaWTix,are prepared via selective laser melting(SLM).A tungsten plate is used as the base material,which is preheated to 180℃to reduce stress.The optimal SLM process parameters are determined through multiple orthogonal tests to prepare samples with good surface formation and no macroscopic cracks.The relative density of the samples is determined via industrial computed tomography(CT)analysis,and the phase composition of the samples is analyzed using Xray diffraction in the range of 10°‒100°.A scanning electron microscope is used to analyze the surface topography and grain distribution of the specimen[electron backscattered diffraction(EBSD)analysis test].Prior to EBSD characterization,the surfaces of the RHEAs are ground with different SiC sandpapers,finely ground with alumina(Al2O3),vibropolished,rinsed with ethanol,and airdried.The compressive properties of the RHEAs are measured using a microcomputercontrolled universal testing machine with a strain of 10-3 s-1 and a specimen size ofφ2 mm×4 mm.At least five samples are selected for compression performance testing,and the average of the test results is calculated to ensure accuracy of compression performance.Results and Discussions The(NbMoTaW)99.5C0.5 RHEA prepared via SLM has a higher dislocation density,and with the continuous thermal cycling of SLM,a large number of

关 键 词：激光技术 难熔高熵合金 激光选区熔化 合金化 显微组织 力学性能 

分 类 号：V252[一般工业技术—材料科学与工程]