利用超声疲劳试验方法分别对室温下医用酒精(体积分数75%)中浸泡5 min、医用酒精浸泡5 min后再在生理盐水中浸泡24 h、直接在生理盐水中浸泡24 h、分析纯乙醇(体积分数99.9%)中浸泡6 h、医用酒精中浸泡6 h等处理条件下退火态Ti6Al4V(TC4)钛合金的超高周疲劳性能进行了研究,并利用扫描电子显微镜(SEM)观察疲劳断面形貌,分析了TC4钛合金的疲劳断裂特性.结果表明:在104 ~ 109周次范围内,经医用酒精处理后TC4钛合金的S-N曲线呈现一次阶梯下降型,而未用医用酒精处理的TC4钛合金的S-N曲线呈现缓慢下降型;在300~700 MPa应力范围内,医用酒精浸泡过的TC4钛合金试样疲劳寿命快速下降;医用酒精处理后的TC4钛合金的超高周疲劳断裂全部从表面发生、断面较光滑且瞬断区面积占比极小,不同于未接触医用酒精的TC4钛合金试样的穿晶塑性断裂.

The ultrasonic fatigue test method was used to investigate the influence of alcohol on the super long life fatigue properties of annealed Ti-6Al-4V (TC4) titanium alloy which were sterillized by 75% medical alcohol for 5 min and dipped into physiological saline solution for 24 h.The fatigue properties of TC4 titanium alloy which subjected to A.R.alcohol for 6 h,directely dipped into 75% medical alcohol for 6 h,and directedly subjected to physiological saline solution for 24 h were also achieved for comparation.The results show that the S-N curves between 104~109 cycles of sterilized TC4 specimen went down with a step,while the S-N curves of specimen without sterization by medical alcohol droped down slowly.75% medical alcohol decreased the fatigue life of TC4 titanium alloy quickly in the maximum fatigue stresses from 300 MPa to 700 MPa.The fractography analysis results show that the fracture always initiated from the surface of specimen which had been sterilized by 75% medical alcohol,and the fracture surface was smooth with small final rupture region,which was different from the transcrystalline plastic fracture of the untreated specimens.