氩弧焊修复激光成形TC11钛合金组织及高周疲劳性能  

Microstructure and high-cycle fatigue properties of laser melting deposited TC11 titanium alloy repaired by tungsten argon arc welding

作　　者：侯慧鹏 田象军[1] 刘栋[1] 王华明[1] 

机构地区：[1]北京航空航天大学材料科学与工程学院,北京100191

出　　处：《焊接学报》2016年第8期9-12,129,共4页Transactions of The China Welding Institution

基　　金：国家"973"项目资助项目(2011CB606305-2);北京市科技计划课题资助项目(D141100003914001)

摘　　要：采用氩弧焊对沉积态激光成形TC11钛合金进行修复并进行双重退火热处理.观察分析了修复试样热处理前后各区域的组织,测试了高周疲劳极限并进行分析.结果表明,修复区宏观组织呈柱状晶形貌,热影响区和基材区呈柱状晶和等轴晶交替排列形貌.热处理前修复区和热影响区为超细针状α相分布在β相基体中,基材区为较细的网篮组织;热处理后各区域的微观组织均为板条状初生α相+β相转变组织,修复区初生α相长度显著大于其它区域.修复件高周疲劳极限下降约7.1%.断口分析表明:修复件疲劳源均为修复区气孔,气孔缺陷是疲劳性能下降的主要原因;疲劳源区呈α相解理、β相撕裂形貌.Tungsten argon arc welding was used to repaira TC11 plate fabricated by laser melting deposition. Duplex-annealing of the repaired sample was provided. Microstructure and high-cycle fatigue properties of the repaired sample were investigated. The results indicated that the repaired zone shows morphology of columnar grains,both heat affected zone and base metal show alternatel yarranged morphology of columnar grains and equiaxed grains. Before heat treatment,the repaired zone and heat affected zone show finen eedle α( hcp) distributed in the β( bcc) matrix,while base metal shows fine basket-weave microstructure. After heat treatment,all zones show microstructure with primary α and transformed β. The primary α phase laths in repaired zone were longer compared with those in other zones. Fatigue properties of the repaired samples were 7. 1%lower than that of the base metal. Fracture analysis of the high cycle fatigue specimens shows that all fatigue sources are porosity in repaired zone. Crack initiation zone is characterized by the crystallographic cleavage facets of α lamellae and tearing of β lamellae.

关 键 词：氩弧焊 修复 激光成形 组织 高周疲劳 

分 类 号：TG444.74[金属学及工艺—焊接]