喷丸表面覆盖率对Ti60高温钛合金疲劳性能的影响

Effect of Shot Peening Surface Coverage on the Fatigue Property in Ti60 High-temperature Titanium Alloy

采用新型的陶瓷弹丸,对Ti60钛合金进行相同喷丸强度和不同表面覆盖率(100%,200%,400%)的喷丸强化,研究了喷丸前后的表面形貌、表面粗糙度、残余应力场、X射线衍射峰半高宽等表面完整性特征参数以及其对高温疲劳寿命的影响。结果表明,喷丸覆盖率对表面完整性具有重大影响,因此不同覆盖率喷丸Ti60钛合金试样具有显著差异的疲劳寿命。采用200%覆盖率喷丸,可以使钛合金Ti60保持较小的表面粗糙度(Ra=1.2μm),较大的尖端圆角曲率半径(相对磨削加工),较好的残余应力分布和稳定的强化层微观组织,这些较好的表面完整性状态使Ti60钛合金的高温旋转弯曲疲劳寿命提高了4倍左右;而采用其他表面覆盖率(100%,400%)喷丸时,Ti60钛合金的高温疲劳寿命提高了2倍左右。

Ti60 high-temperature titanium alloy was peened by the ceramic shot,with the same shot peening intensity and the different coverages（100%,200% and 400%）.The changes of surface integrity such as surface morphology,roughness,residual stress profile and full wave at half maximum caused by different coverage shot peening and their effects on high temperature fatigue life were investigated.The results show that the shot peening coverage has a significant influence on surface integrity,so that high temperature fatigue property of Ti60 titanium differs under different surface coverage.However,compared with the other surface coverage,Ti60 titanium alloy has the smoother surface（Ra=1.2 μm）,larger micro-notch radius,excellent residual stress profile and stable micro-structure when shot peened under 200% surface coverage,and the high temperature rotating-bending fatigue life on Ti60 titanium was improved by about 4 times due to the perfect surface integrity.Moreover,the high temperature fatigue life was improved by about 2 times when shot peened under 100% and 400% surface coverages.