喷丸对TC4钛合金残余压应力场及疲劳寿命的影响

摘要

The effects of different shots and shot peening processes on surface morphology, surface plastic deformation, compressive residual stress field and fatigue life of TC4 titanium alloy after shot peening were studied. The results show that compared with the TC4 titanium alloy strengthened by cast steel shot, the surface of the alloy strengthened by ceramic shot had little fluctuation, but the working marks could be covered effectively. The surface cumulative plastic deformation on sample surface raised firstly and then saturated with the increase of shot pressure and shot time. The maximal compressive residual stress and the deepth of residual stress field could reach 610 MPa and 250 tim, respectively, either when the peening time was more than 40 s using east steel shot or when the peening time was more than 80 s using ceramic shot with the shot pressure of 0. 25 MPa. The fatigue life of TC4 titanium alloy increased by more than 10 times and 20 times, respectively, after shot peening strengthening with the two shots.%研究了不同弹丸及喷丸参数对喷丸后TC4钛合金表面形貌、表面塑性变形程度、残余压应力场和疲劳寿命的影响。结果表明：与铸钢弹丸相比，陶瓷弹丸喷丸强化后TC4钛合金表面的起伏程度变化不大，但能有效地覆盖加工刀痕；随喷丸压力增大和喷丸时间延长，试样表面的累积塑性变形先快速增大后趋于饱和；当喷丸压力达到O．25MPa、铸钢弹丸喷丸时间大于40S或陶瓷弹丸喷丸时间大于80S时，最大残余压应力可达到610MPa，残余压应力场深度超过250μm；两种弹丸喷丸强化后，Tc4钛合金的疲劳寿命分别可提高10倍和20倍以上。