喷丸对TB6钛合金疲劳应力集中敏感性的影响

Effect of Shot Peening on Fatigue Stress Concentration Sensitivity of TB6 Titanium Alloy

针对航空用TB6高强钛合金,本工作研究了应力集中条件下喷丸对其疲劳性能的影响规律。采用旋转弯曲疲劳试验机分别测试了两种应力集中系数的试棒的疲劳寿命及极限,采用扫描电镜分析了疲劳断口,采用MTS试验机测试了试棒的拉伸性能,并采用白光干涉仪测试了试样的表面形貌。结果表明:当应力集中系数由K_(t)=1提高至K_(t)=2时,TB6钛合金试棒的疲劳极限从537.5 MPa下降至335.5 MPa,表现出明显的应力集中敏感性。而经过喷丸后,K_(t)=1和K_(t)=2的试棒的疲劳极限分别提高了33.5%和22.2%,缺口敏感性下降了48%。喷丸有利于降低TB6钛合金的疲劳应力集中敏感性。

The effect of shot peening on the fatigue performance of aviation TB6 titanium alloy specimens with high strength under stress concentration condition was investigated.The fatigue life/limits,fracture,tensile property and surface morphology were tested by the rotation bending fatigue tester,scanning electron microscopy,MTS tester,and white light interferometer.The results show that the fatigue limit of TB6 titanium alloy decreases from 537.5 MPa to 335.5 MPa as the increase of stress concentration ratio from K_(t)=1 to K_(t)=2.The alloy shows high fatigue stress concentration sensitivity.After shot peening,the fatigue limit of specimens with K_(t)=1 and K_(t)=2 increases by 33.5%and 22.2%,respectively.The notched sensitivity decreases by 48%.The shot peeing is beneficial to decreasing the fatigue stress concentration sensitivity of TB6 titanium alloy.