TiAl金属间化合物电子束焊接头应力场分布特征

采用热弹塑性有限元方法,对TiAl金属间化合物平板电子束焊接接头的焊接应力进行了三维数值模拟,并分析了应力分布状态与裂纹特征之间的关系.结果表明,沿焊缝方向σx为残余拉应力,在焊道中部维持在较高水平,最高拉应力为390MPa.焊道中部横截面σx方向为残余拉应力,在热影响区附近达到最大值415 MPa,σy方向也为残余拉应力,且在距焊缝中心1.9 mm处达到最高值160 MPa左右.在不同焊接热输入条件下接头最高抗拉强度为304.7 MPa,断裂发生在接头热影响区附近,即残余应力最大的区域.

Distributive characteristic of stress field in electron beam welded joint of TiAl intermetalics plates

Welding stress in electron beam welding joint of TiAl intermetalics plates, as well as the relationship between stress distribution and crack characteristic were numerical stimulated using thermo-elastic-plastic finite element method. The results showed that stress σ_x along welding direction was tensile stress, and which was a relatively high level in central weld. With the highest value of 390 MPa, σ_x in the cross section in central weld was tensile stress and it came to the largest value of 415 MPa in HAZ. In the same section, σ_y perpendicular to welding direction was also tensile stress and the largest value was approximately to 160 MPa at the site 1. 9 mm away from weld center line. The highest tensile strength of the joints welded under different heat inputs was 304. 7 MPa. Fracture occured near HAZ, e. g. the place where the residul stress value was the largest from the numerical simulation results.