金属及合金的疲劳性能和疲劳行为是影响其长期安全服役的一个重要的因素.本文主要研究了锻造态和退火态Ti-20Zr-6.5Al-4V(简称TZ20)的疲劳行为和疲劳机制.XRD结果表明,锻造态和退火态两种状态的TZ20合金均由α相和β相组成.微观组织分析表明,虽然两种状态下该合金都呈现出典型的网篮组织特征,但是其各相含量及其晶粒尺寸有较大的区别.疲劳实验结果表明,锻造态和退火态合金的条件疲劳极限σ0.1(107)分别为623 MPa和 572 MPa.疲劳断口分析表明,锻造试样疲劳断口具有多个疲劳裂纹源,而退火试样的疲劳断口只有一个疲劳裂纹源.%Fatigue behavior and properties of metal and alloys is a key factor for ensuring long time and safely applications.The aim of this work is to investigate the fatigue behavior and mechanism of the Ti-20Zr-6.5Al-4V (shorted as TZ20) alloy after forging and annealing treatments.After both forging and annealing treatments, the TZ20 alloy has typical basketweave microstructure which has the characteristic of plate α grains and retained β phase.Although the TZ20 alloy with both states has similar structure, their fatigue behavior and corresponding properties showed obviously difference.The conditional fatigue limit σ0.1(107) is 623 and 572 MPa for forged and annealed specimens, respectively.Fatigue fractured surface analysis also showed different fracture mechanism.Only one crack initiated on surface for annealed specimen but two initiations for forged one were observed in the fatigue fracture surface.
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