钛合金零件残余应力消除及形状精度保持性研究

Study on Residual Stress Relief and Shape Accuracy Retention of Titanium Alloy Parts

将真空去应力退火、深冷处理和高低温循环热处理进行组合,对航天器结构产品中常用的TC4 R态钛合金典型样件开展残余应力消除试验,并采用X射线衍射法对样件进行残余应力测量,计算处理后样件内部和表面残余应力的平均消除率,最后对处理后样件进行形状精度检测,验证各种热处理方法对形状精度保持性的效果。结果表明,真空去应力退火最为有效,深冷处理次之,高低温循环热处理效果最差,残余应力平均消除率的大小和形状精度保持性的好坏呈强正相关性。相对于未经处理的样件,经真空去应力退火+深冷处理+高低温循环热处理样件的内部/表面残余应力平均消除率和形状精度保持性最高,经真空去应力退火+高低温循环热处理样件的次之,经深冷处理+高低温循环热处理样件的再次之,只经高低温循环热处理样件的最低。

Residual stress relief tests are carried out on typical TC4 R state titanium alloy commonly used in spacecraft structural products by vacuum stress relief annealing,cryogenic treatment,and high and low temperature cyclic heat treatment.X-ray diffraction method is used to measure residual stress in the specimens,and the average residual stress relief rates inside and in the surface of the treated specimens are calculated.Finally,the shape accuracies of the treated specimens are tested,and the effectiveness of various heat treatment methods in maintaining shape accuracy is verified.The results show that the vacuum stress relief annealing is the most effective,followed by cryogenic treatment,and that the effectiveness of high and low temperature cyclic heat treatment is the lowest.The average residual stress relief rate is strongly positively correlated with the shape accuracy retention.Of all the specimens treated by different methods,the average residual stress relief rates in the internal/surface of specimens treated with the combination of vacuum stress relief annealing,cryogenic treatment,and high and low temperature cycle heat treatment in queue are the highest,and their shape accuracy retention the best,those of the specimens treated with cryogenic treatment and high and low temperature cycle heat treatment come in second,and those of the specimens only treated with high and low temperature cyclic heat treatment rank last.