Influence of Alcohol on the Super Long Life Fatigue Properties of TC4 Titanium Alloy

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.