TC21钛合金显微组织对超长寿命疲劳行为的影响

本文主要研究钛合金的网篮尺寸对于超声疲劳行为的影响。研究发现,对于TC21钛合金,高应力下疲劳裂纹萌生于试样表面;低应力下疲劳裂纹萌生于试样亚表面。最大应力-循环次数(S-N)曲线显示,在两段连续下降的曲线之间有一个表面萌生向内部萌生的转变平台。对于网篮尺寸为60μm的钛合金,转变平台对应的应力幅为540MPa,疲劳极限为430MPa。网篮尺寸为40μm的转变平台应力幅为600MPa,疲劳极限为530MPa。分析得知网篮尺寸为60μm的TC21钛合金疲劳性能低于网篮尺寸为40μm的TC21钛合金。

On the Effect of Microscopic Structure on Super Long Life Fatigue Behavior of TC21 Titanium Alloy

This paper mainly studies the influence of titanium alloy basket size on ultrasonic fatigue behavior.Study reveals that for TC21 titanium alloy,fatigue cracks initiate at specimen surface under high stress,while under lower stress,fatigue cracks initiate at the subsurface of specimen.S-N curve indicates that there is a transition platform between two continuous descent curve sections,which reflects the transformation from the surface cracks to the interior cracks.For titanium alloy with basket size of 60μm,the stress amplitude corresponding to the transition platform is 540MPa,and the fatigue limit is 430MPa;for titanium alloy with basket size of 40μm,the stress amplitude corresponding to the transition platform is 600MPa,and the fatigue limit is 530MPa.Comparative analysis shows that the fatigue properties of TC21 titanium alloy with basket size of 60μm are lower than that of TC21 titanium alloy with basket size of 40μm.