论文部分内容阅读
采用统计分析的方法研究了固溶氢对TC4钛合金电子束焊接头疲劳寿命的影响,并对接头试样的疲劳断裂位置和疲劳断口形貌进行了观察与分析。结果表明,氢显著降低了TC4钛合金试样的疲劳寿命,氢含量0.028%(质量分数)的钛合金的疲劳寿命仅为未充氢试样的一半,当氢含量增大到0.120%时,疲劳寿命降到了未充氢的五分之一。疲劳试样多数断于接头的热影响区,造成这一结果的主要原因是热影响区的组织不均匀性和氢含量相对较高。断口的形貌特征表明,氢促进了疲劳裂纹的萌生和增加了裂纹扩展的速度,导致钛合金电子束焊接头的疲劳寿命显著降低。
The influence of solution hydrogen on the fatigue life of the electron beam welded joint of TC4 titanium alloy was studied by means of statistical analysis. The fatigue fracture location and fatigue fracture appearance of the joint specimen were observed and analyzed. The results show that hydrogen significantly reduces the fatigue life of TC4 titanium alloy. The fatigue life of titanium alloy with hydrogen content of 0.028% (mass fraction) is only half of that of non-hydrogenated sample. When the hydrogen content increases to 0.120% Fatigue life dropped to one-fifth of the hydrogen is not filled. The majority of fatigue specimens were broken in the HAZ of the joint, the main reason for this is the relatively non-uniform microstructure and relatively high hydrogen content in the HAZ. The morphology of the fracture shows that hydrogen promotes the initiation of fatigue cracks and increases the rate of crack propagation, leading to a significant decrease in the fatigue life of the titanium alloy electron beam welded joints.