植入用钛合金经模拟体液浸泡后的超高周疲劳性能

为预测植入用Ti6A14V钛合金的使用寿命，研究其体液环境下的超高周疲劳性能，将退火态Ti6A14V钛合金试样恒温37℃在人工唾液和林格一洛克氏溶液中预浸泡2周．利用超声疲劳试验技术对预处理过的试样进行疲劳测试；利用电子显微镜观察疲劳断口，研究其裂纹萌生机理．结果表明，2种模拟体液浸泡后材料在107周次前的高应力范围内，疲劳强度均降低且裂纹一般萌生于试样表面；而在107周次后的超长寿命域，疲劳强度均跟未处理试样数据接近．且裂纹在内部萌生．主要由内部缺陷附近α相滑移引起．

Ultra-high Cycle Fatigue Performance of Implanted Titanium Alloy After Soaked in Simulated Body Fluid

To predict the service life of Ti6A14V implants and to study its ultra-high cycle fatigue properties after subjected to simulated body fluid environment, annealed Ti6A14V specimens were subjected to artificial saliva and Ringer-Locke＇s solution （37 ℃） for two weeks in two groups. The ultra-high cycle fatigue properties was examined by ultrasonic fatigue testing technique and the crack initiation mechanism was investigated with scanning electron microscopy. Results showed that the subjection to simulated body fluid decreases the fatigue strength of Ti6A14V in the region less than 107 cycles while the fatigue strength is similar with untreated specimens in the ultra-high cycles region （〉107 cycles）. Cracks initiateed because of the slip of a-phase at the internal defects in the ultra-high cycles region instead of surface cracks of specimens with the fatigue life less than 107 cycles.