异种高温钛合金电子束焊接接头组织与性能

Microstructure and properties of electron beam weldedjoints of dissimilar high temperature titanium alloys

采用真空电子束焊机对高温钛合金Ti60板材和Ti700sr铸件进行焊接,并对接头显微组织和力学性能进行了研究.结果表明,高温钛合金Ti60板材和Ti700sr铸件电子束焊接性良好,可以获得优质的接头.获得的接头中焊缝为细小针状马氏体组织,Ti700sr侧熔合区马氏体内部存在层错和孪晶.Ti700sr侧热影响区相比于母材网篮状的α相长大.Ti60侧熔合区和热影响区均发现富Nd稀土弥散相析出.焊缝区显微硬度与Ti60和Ti700sr母材相当,基本在360 HV左右.硬度最高点出现在Ti60侧热影响区,硬度最大值达到418 HV.接头室温抗拉强度达到1100 MPa以上,断裂于Ti60热影响区.接头600和650℃高温抗拉测试均失效断裂在Ti60母材.其中接头600℃高温拉伸性能均值为695 MPa,650℃高温拉伸性能均值为587 MPa.

High temperature titanium alloy Ti60 plate and Ti700sr casting were welded by vacuum electron beam welding machine,and the microstructure and mechanical properties of the joint were studied.The results show that the high temperature titanium alloy Ti60 plate and Ti700sr casting have good weldability by electron beam welding,and high quality joint can be obtained.The welding seam in the joint is fine acicular martensite,and there are stacking faults and twins infusion zone of Ti700sr side.Theαphasein the HAZ of Ti700sr grow a lot compared with theαphase in the base metal.There are rich rare earth Nd precipitates in the fusion zone and heat affected zone on the Ti60 side.The microhardness of the weld metal is similar to that of Ti60 and Ti700sr,which is about 360 HV.The highest hardness occurs in the heat affected zone of Ti60 side,and the maximum hardness reaches 418 HV.The tensile properties of the joints at 600 and 650℃are 695 and 587 MPa respectively.