| Titanium alloy is one of the most widely used in light metal. It has many properties, such as good corrosion resistance, high specific strength and high temperature properties, titanium alloy is main alloy for the aerospace and navigation industry; titanium and titanium alloys also have low elastic modulus, close to bone density, fine biocompatibility and good corrosion resistance, so it can be used as medical implants and medical devices materials. Alcohol is the most important cleaning solution in daily life. Titanium alloy will inevitably contact with alcohol or alcohol environment when be used. The titanium alloy is prohibited to contact with alcohols in American airlines standard specifications, but it did not specify the impact of alcohol on titanium alloys. So, study the effect of alcohol to the mechanical properties of titanium alloy is necessary. The titanium alloy of TC4(Ti-6Al-4V) is selected for the study in this paper. TC4alloy has many merits, such as high strength, high toughness, and high heat resistance, good forging and stamping performance, so the TC4become the ace of the alloys in the titanium industry, all titanium are accounted for70%in the titanium industry. Many other titanium alloys are modified on the basis of TC4.In this paper, completed TC4alloy tensile test for dipped into alcohol solution with not dipped into alcohol solution by using the MTS. The test indicates that alcohol solution has no effect on TC4titanium elastic modulus, yield strength, tensile strength, elongation and reduction of area rate.The high cycle fatigue test of TC4alloy dipped into alcohol solution and not dipped into alcohol solution in the104～107cycles is tested by using electromagnetic high cycle fatigue machine, frequency is in the range of110Hz～120Hz and stress ratio is R=0.1. And the ultra-high cycle fatigue test of TC4alloy for two samples in the106～109cycles is tested by ultrasonic fatigue testing machine, frequency is20kHz and stress ratio is R=-1. The tests indicate that S-N curves of the specimen decrease obviously after dipped into alcohol solution, and S-N curves of TC4alloy display decline slowly in high cycle fatigue and ultra-high cycle fatigue. The fracture surfaces of specimens were investigated and analyzed with scanning electron microscopy (SEM) and energy dispersive atomic X-ay (EDAX). Fatigue fracture of TC4alloy included not only surface crack initiation but also internal initiation, but surface crack initiation is main fracture morphology. And a number of fatigue sources of fracture morphology also can be observed. And TC4alloy crack initiation mechanism is analyzed. The authors believe that Al enrichment is a major cause of crack initiation. |
