组织对医用Ti-3Zr-2Sn-3Mo-25Nb钛合金低周疲劳行为及变形机制的影响

Effect of microstructure on low cycle fatigue behavior and deformation michenisms of Ti-25Nb-3Mo-2Sn-3Zr alloy for biomedical application

摘要:

本文研究了具有两种不同组织(固溶态、时效态)的Ti-3Zr-2Sn-3Mo-25Nb(TLM)合金在室温应变控制的低周疲劳循环变形行为及微观变形机制。结果表明：TLM合金的循环硬化/软化行为与应变幅和组织密切相关。固溶态合金的低周疲劳寿命更高,且弹性模量均随循环周次和总应变幅的增大,从保持不变到急剧增加,时效态的弹性模量则在循环变形过程中基本保持不变。微观组织特征表明,固溶态合金的循环变形机制主要依赖位错滑移、变形诱发的α″马氏体和独特的“Z”型β孪晶协同作用,而时效态合金则只是以位错滑移为主。

Abstract:

Cyclic deformation behavior and micromechanisms in strain controlled low cycle fatigue of a near β-Ti alloy Ti-3Zr-2Sn-3Mo-25Nb (TLM) with the different microstructures, which are solution treatment and aging treatment conditions, were comparatively investigated at room temperature. The results showed that the cyclic hardening/softening behavior of TLM alloy was significantly correlated with strain amplitude and microstructure.SThe low cycle fatigue life of the alloy at the solution treatment was higher, and the elastic modulus increased from constant to sharp with the increase of cycle number and total strain amplitude, while the elastic modulus of the aged alloy had a little change during the cycle deformation.SThe microstructure characteristics showed that deformation mechanism of the solid solution alloy was mainly dependent on the formation and their interaction of dislocation slip, the deformation-induced α martensites and the unique "Z" type β twin, while the aging alloy was mainly dependent on dislocation slip.