喷丸强化因素对钛合金固体粒子冲蚀抗力的影响

探讨了喷丸强化(SP)因素(残余压应力引入、表面粗糙度增大和表面加工硬化等)对Ti6Al4V钛合金固体粒子冲蚀(SPE)行为的影响和作用机制,为充分发挥SP改进航空发动机零部件服役性能的潜力提供依据。结果表明:Ti6Al4V合金表面直接喷丸处理,其SPE抗力无明显改变;SP处理后进行表面抛光,Ti6Al4V合金SPE抗力明显增加。SP造成的表面粗糙度增大导致了钛合金在大小冲击攻角下的SPE抗力的下降;SP引入的表面残余压应力对提高钛合金在90°大攻角下的SPE抗力起了重要作用,原因是SP残余压应力增加了裂纹闭合力和抑制了疲劳裂纹早期扩展;SP引起的表面加工硬化作用对提高钛合金在30°小攻角下的SPE抗力有重要贡献,这归于加工硬化提高了材料表面在小攻角下的微犁削抗力。

Effect of Shot Peening Factors on Solid Particle Erosion Resistance of Titanium Alloy

The effects of three factors,i.e.,compressive residual stress(CRS),surface roughness(SR) and micro-structure hardening in shot peening(SP) surface on solid particle erosion(SPE) resistance of Ti6Al4V titanium alloy were evaluated.The mechanism of SP on SPE was investigated.The study provides guide for making use of the potential of SP in improving aero-engine component′s service performance.The results show that the SPE resistance of Ti6Al4V alloy can not be improved obviously by only shot peening,but with polishing treatment to the shot peening specimen,the SPE resistance can be improved obviously.Surface roughing by SP decreases the SPE resistance of the Ti alloy at any impingement angle.Compressive residual stress induced by SP arrests the crack into closure and slows fatigue crack propagation.Thus the SPE resistance is improved by SP with polished surface at impingement angle of 90°.Micro-structure hardening improves the SPE resistance of the titanium alloy at impingement angle of 30° because the micro cutting resistance of the alloy surface is increased.