激光选区熔化成形Ti6Al4V钛合金叶片的超高周疲劳行为  

Ultra-high cycle fatigue behavior for Ti6Al4V titanium alloy blade formed by selective laser melting

作　　者：门正兴[1] 郑金辉[1] 王昌飞 张宏 刘建超[1] 马亚鑫 岳太文[1] Men Zhengxing;Zheng Jinhui;Wang Changfei;Zhang Hong;Liu Jianchao;Ma Yaxin;Yue taiwen(Mechanical and Electrical Engineering Department,Chengdu Aeronautic Polytechnic,Chengdu 610021,China;Chengdu Yonsea Addform Technologies Co.,Ltd.,Chengdu 610021,China;Failure Mechanics and Engineering Disaster Prevention and Mitigation Key Laboratory of Sichuan Province,College of Architecture and Environment,Sichuan University,Chengdu 610065,China)

机构地区：[1]成都航空职业技术学院,机电工程学院,四川成都610021 [2]成都雍熙聚材科技有限公司,四川成都610021 [3]四川大学,建筑与环境学院,破坏力学与工程防灾减灾四川省重点实验室,四川成都610065

出　　处：《锻压技术》2020年第11期89-93,125,共6页Forging & Stamping Technology

基　　金：四川省科技厅项目(2019YJ0519);中国博士后基金(2019M653396);四川大学-自贡政府战略合作支持项目(2019CDZG-4);四川大学-宜宾政府战略合作支持项目(2019CDYB-24);四川大学博士后基金(2019SCU12056)。

摘　　要：疲劳寿命低是限制激光选区熔化成形(SLM)零件在航空领域广泛应用的主要瓶颈。采用超声疲劳的试验方法对激光选区熔化成形Ti6Al4V钛合金叶片开展了超高周疲劳性能与断裂机理的试验研究,采用金相显微镜、扫描电镜分别对Ti6Al4V钛合金叶片进行微观组织及疲劳断口的形貌观察。试验结果表明:随着应力幅值的下降,SLM成形的Ti6Al4V钛合金叶片的疲劳寿命呈现线性上升的趋势,在109疲劳寿命下的疲劳强度为280 MPa。SLM成形的Ti6Al4V钛合金叶片的超高周疲劳裂纹的萌生位置存在竞争机制,即内部与次表面的竞争萌生。材料的孔洞性缺陷最终决定裂纹的萌生位置和扩展速度,孔洞性缺陷的尺寸直接决定了疲劳寿命。Poor fatigue life is the main bottleneck that restricts the wide application of selective laser melting(SLM)parts in the aviation field.Therefore,the ultra-high cycle fatigue properties and fracture mechanism of Ti6Al4V titanium alloy blade by SLM were studied by ultrasonic fatigue test method,and the microstructure and fatigue fracture morphology of Ti6Al4V titanium alloy blade were observed by metallographic microscope and scanning electron microscope respectively.The test results show that with the decreasing of stress amplitude,the fatigue life of Ti6Al4V titanium alloy blade formed by SLM shows a linear upward trend,and the fatigue strength is 280 MPa under the fatigue life of 109.Furthermore,there is a competitive mechanism in the initiation position of ultra-high cycle fatigue crack in Ti6Al4V titanium alloy blade formed by SLM,that is,the internal and subsurface competition initiation.In addition,the hole defect of material ultimately determines the crack initiation position and growth rate,and the size of hole defect directly determines the fatigue life.

关 键 词：激光选区熔化 TI6AL4V钛合金 超高周疲劳 疲劳寿命 孔洞性缺陷 

分 类 号：TG316[金属学及工艺—金属压力加工]