超缓慢加热处理对激光沉积制造Ti-5Al-4Mo-3V-2Zr-Nb近β钛合金组织与性能的影响  

Influence of Ultra-Slow Heating Treatment on Microstructure and Properties of Ti-5Al-4Mo-3V-2Zr-Nb NearβTitanium Alloy Fabricated by Laser Deposition

作　　者：周思雨 方明晨 杨光 孙中刚 张思远[4] 李长富 Zhou Siyu;Fang Mingchen;Yang Guang;Sun Zhonggang;Zhang Siyuan;Li Changfu(College of Mechanical and Electrical Engineering,Shenyang AerospaceUniversity,Shenyang 110136,Liaoning,China;Structure Department,Shenyang Aircraft Design and ResearchInstitute,Aviation Industry Corporation of China,Ltd.,Shenyang 110035,Liaoning,China;College of Materials Science and Engineering,Nanjing Tech University,Nanjing 211816,Jiangsu,China;Northwest Institute for Non-Ferrous Metal Research,Xi’an 710016,Shaanxi,China)

机构地区：[1]沈阳航空航天大学机电工程学院,辽宁沈阳110136 [2]中国航空工业集团有限公司沈阳飞机设计研究所结构部,辽宁沈阳110035 [3]南京工业大学材料科学与工程学院,江苏南京211816 [4]西北有色金属研究院,陕西西安710016

出　　处：《中国激光》2024年第20期245-252,共8页Chinese Journal of Lasers

基　　金：国家重点研发计划(2021YFC2801903,2022YFB4602201);国家自然科学基金(52005351);沈阳市中青年科技创新人才支持计划(RC220449)。

摘　　要：研究了超缓慢加热处理对激光沉积制造Ti-5Al-4Mo-3V-2Zr-Nb近β钛合金显微组织与力学性能的影响。结果表明,沉积态试样的显微组织由板条状的α相和β相及细针状的次生α相组成,同时在β晶界处存在连续的线性晶界α相,且在周围伴随连续的无析出区。引入超缓慢加热处理后,α相发生尖端溶解现象并粗化,转变为短棒状α相。连续的晶界α相发生断裂,连续的无析出区消失。沉积态的抗拉强度和屈服强度分别为1077.5 MPa和1066.4 MPa,断后伸长率为9.8%,断裂模式为韧脆混合断裂。而在引入超缓慢加热处理后,试样抗拉强度和屈服强度分别为1015.8 MPa和990.1 MPa,断后伸长率为15.6%,断裂模式为韧性断裂。这是因为经过超缓慢加热处理后,初生α相与次生α相发生粗化,抵抗塑性变形的能力减弱,在同样外部载荷作用下α相与β基体的应变差减小,与β相协调变形的能力增加,材料的塑性得到改善。Objective Ti-5Al-4Mo-3V-2Zr-Nb(hereinafter referred to as Ti-5321G)is a metastableβalloy with high specific strength and excellent corrosion resistance and has a wide range of applications in the aerospace field.Laser deposition manufacturing(LDM)is a layer-by-layer manufacturing method with high material utilization,high freedom of forming and almost unlimited material types.However,Ti-5321G samples formed through LDM generally have continuous linear grain boundaries ofαphase,resulting in poor strength-ductility match.Thus,the application of Ti-5321G is extremely limited.Therefore,it is necessary to perform specific heat treatment on Ti-5321G formed through LDM to disrupt the continuous linear grain boundaries ofαphase and improve its strengthductility match.Ultra-slow heating treatment(SHT)is employed to break the continuous linear grain boundaries ofαphase and enhance material strength-ductility match.The influence of slow heating treatment on the microstructure and properties of Ti-5321G is investigated.Methods First,Ti-5321G samples are formed through LDM.Second,the as-deposited Ti-5321G samples are annealed at 870℃for 0.5 h and then water-quenched.Subsequently,the samples are heated to 810℃at a heating rate of 1.24℃/min and held for 2 h.The samples are then furnace-cooled to 730℃,held for 2 h,and air-cooled,followed by 580℃/4 h aging treatment.Third,the microstructure of Ti-5321G samples formed by LDM after ultra-slow heating treatment is observed using optical microscope(OM)and scanning electron microscope(SEM).The content and size ofαphase are measured using Image pro plus 6.0.Finally,tensile tests are conducted on the samples,and the fracture morphology is observed using SEM for performance evaluation.Results and Discussions The microstructure of Ti-5Al-4Mo-3V-2Zr-Nb samples formed through LDM is shown in Fig.3.It is characterized by plate-like primaryαphase(αp)and residualβphase,with secondaryαphase(αs)distributed in a needle-like manner in the gaps ofαp.Linear continuous grain boun

关 键 词：激光沉积制造 超缓慢加热处理 组织性能 断裂机制 Ti-5Al-4Mo-3V-2Zr-Nb 

分 类 号：TG166.5[金属学及工艺—热处理]