激光沉积Ti65钛合金显微组织和疲劳性能  

Laser deposition of Ti65 titanium alloy microstructure and fatigue properties

作　　者：李晓丹[1] 孙浩军 殷俊[1] 倪家强 周松 安金岚 张宏杰 LI Xiaodan;SUN Haojun;YIN Jun;NI Jiaqiang;ZHOU Song;AN Jinlan;ZHANG Hongjie(Shenyang Aircraft Corporation.Shenyang,110850,China;School of Mechanical and Electrical Engineering,Shenyang Aerospace University,Shenyang,110136,China;Shenyang Aircraft Design Institute,Shenyang,110135,China;Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process,Shenyang Aerospace University,Shenyang,110136,China)

机构地区：[1]沈阳飞机工业(集团)有限公司,沈阳110850 [2]沈阳航空航天大学,机电工程学院,沈阳110136 [3]沈阳飞机设计研究所,沈阳110135 [4]沈阳航空航天大学,航空制造工艺数字化国防重点学科实验室,沈阳110136

出　　处：《焊接学报》2024年第10期97-104,共8页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(52105157);中国博士后科学基金资助项目(2023 MD734242);辽宁省教育厅重点攻关项目(JYTZD2023007)。

摘　　要：采用单一变量法研究了激光功率和温度对激光沉积制造Ti65钛合金高周疲劳性能的影响,通过光学显微镜、超声波探测仪和扫描电镜(scanning electron microscope,SEM)对试样的显微组织、内部缺陷和断口形貌进行了分析.结果表明,不同功率试样的显微组织均为网篮组织,α相的含量明显高于β相的含量,高温下网篮组织中的α相发生粗化,晶粒内部出现一些块状α相,组织的均匀性下降.室温和高温条件下高功率和低功率试样的疲劳极限分别为454,398.5,371.5 MPa和336.25 MPa,同一温度下,高功率试样的疲劳极限要比低功率试样的疲劳极限高10%以上;同一功率下,室温试样的疲劳极限要比高温试样的疲劳极限高18%以上,温度对于高周疲劳的影响更大.激光沉积制造Ti65钛合金试样内部存在气孔缺陷,低功率试样中气孔的数目多且直径大,其疲劳源均形核于气孔缺陷处,气孔直径越大,距离表面距离越近,裂纹萌生的越快,疲劳寿命越低,高功率试样中气孔的数目少且直径小,其疲劳源均萌生于表面裂纹,缺陷的存在对裂纹的萌生存在很大影响.The effects of laser power and temperature on the high-cycle fatigue properties of Ti65 titanium alloy fabricated by laser deposition are studied by single variable method,and the microstructure,internal defects and fracture morphology of the samples are analyzed by optical microscope,ultrasonic detector and scanning electron microscope(SEM).The results show that the microstructure of the samples with different power is the basket structure,and the content of theαphase is significantly higher than that of theβphase,and theαphase in the basket structure is coarsenized at high temperature,and some massiveαphases appear inside the grain,and the uniformity of the structure decreases.The fatigue limits of high-power and low-power samples at room temperature and high temperature are 454,398.5,371.5 MPa and 336.25 MPa,respectively,and the fatigue limits of high-power samples are more than 10%higher than those of low-power samples at the same temperature.At the same power,the fatigue limit of the room temperature sample is more than 18%higher than that of the high temperature sample,and the temperature has a greater influence on the high cycle fatigue.There are porosity defects in Ti65 titanium alloy specimens made by laser deposition,and the number of pores in low-power specimens is large and the diameter is large,and the fatigue source is homogeneously nucleated at the porosity defects.The larger the diameter of the pores,the closer the distance from the surface,the faster the crack initiation,the lower the fatigue life,the number of pores in the high-power sample is small and the diameter is small,the fatigue source is germinated in the surface crack,and the existence of defects has a great impact on the germination of cracks.

关 键 词：激光沉积 Ti65钛合金 高周疲劳 裂纹萌生 

分 类 号：TG456.7[金属学及工艺—焊接]