TC4钛合金线性摩擦焊接头组织及残余应力分布特征

摘要

Using microscopy and X ray dif-fraction technology, a detailed investigation on the micro-structural and residual stress distribution in linear friction welded Ti–6Al–4V is performed. The results show that, during welding process, the equiaxedαand transformedβin thermo-mechanically affected zone is elongated and broken, and the microstructure in welded zone is ultra-ifne grain. Residual stress distribution of the joint only has tensile stress zone in one side, compared with the other side which contains both tensile stress zone and compress stress zone. In the transverse section of welding line, re-sidual stress in transverse direction presents V and W type distribution patterns at the center of welding line and at both ends of welding line respectively. While, in the lon-gitudinal section of welding line, high tensile stress in the central part is the distribution characteristic of longitudinal direction of residual stress, changing to compress stress near both ends of welding line gradually.%使用光学显微镜和X射线衍射法对TC4钛合金线性摩擦焊接头组织和残余应力分布特征进行研究。结果表明：热机影响区内的α相和β转变体在线性摩擦焊接过程中被不同程度地拉长，变形严重，焊缝区存在超细晶粒区。焊后接头的残余应力场表现为在一侧为拉应力，而在另一侧同时存在拉应力区和压应力区。垂直于焊缝的横截面上，垂直焊缝方向的残余应力在焊缝中心和焊缝端部分别呈现V字形和W字形分布特征，而在焊缝纵截面上，平行焊缝方向的残余应力分布特征为中心段存有较高的残余拉应力，至焊缝两端逐渐下降为压应力。