表面加工方法对TC4钛合金表面完整性及高周疲劳性能的影响

摘要

研究了磨削、一次喷丸、二次喷丸3种表面加工方法对TC4钛合金表面完整性及高周疲劳性能的影响规律,采用白光干涉仪、X射线残余应力测试仪对经不同方法加工的试样的表面形貌、表面粗糙度和表面残余应力分布等表面完整性参数进行了表征.采用旋转弯曲疲劳试验机分别测试了不同方法加工的光滑试样(应力集中系数Kt＝1)和缺口试样(Kt＝2)的旋转弯曲疲劳S-N曲线.结果表明,相比磨削,一次喷丸和二次喷丸处理后TC4钛合金光滑试样和缺口试样的疲劳极限均显著提高,TC4钛合金的疲劳缺口敏感性下降.另外,二次喷丸的疲劳极限增益效果优于一次喷丸的,原因是二次喷丸在TC4钛合金表面形成了更优的残余压应力场分布和更低的表面粗糙度.%The effect of grinding(GD), single shot peening(SSP), and double shot peening(DSP) methods on the surface integrity and the high-cycle fatigue property of TC4 titanium alloy was investigated.The surface topography, surface roughness and residual stress distribution were characterized by white light interferometer (WLI) and X-ray diffraction(XRD) stress tester.The rotating-bending fatigue S-N curves with un-notched specimens (stress concentration factor Kt＝1) and notched specimens(Kt＝2) were investigated.The results indicate that, compared with specimens by GD, the fatigue limits both increase largely by SSP and DSP regardless of the un-notched and notched specimens. Furthermore, the improvement on the fatigue property of DSP is better than that of SSP.It is attributed to the better residual stress distribution and the lower surface rough value on the surface of TC 4 titanium alloy after DSP.