【摘要】 采用应变控制的方法,研究了铸造Ti-48Al-2Cr-2Nb合金400℃～800℃循环温度下的同相位热机械疲劳行为,并与400℃和800℃恒温低周疲劳结果进行了对比分析。结果表明,该合金的400℃～800℃同相位热机械疲劳性能在大应变短寿命区优于400℃和800℃恒温低周疲劳;在小应变长寿命区略低于400℃低周疲劳,介于800℃低周疲劳数据分散带内;在热机械疲劳试验条件下,合金不表现明显循环硬化或软化现象,疲劳试样断口可观察到层片间、层片内断裂和穿层片撕裂3种开裂方式。更多还原

【Abstract】 The thermo-mechanical fatigue( TMF) behavior of casting alloy Ti-48 Al-2 Cr-2 Nb was researched. The tests were performed thermo-mechanically in-phase( IP) at 400℃ ～ 800℃ . During TMF,tests strain was controlled. The result of this IP TMF was compared with 400℃ and 800℃ isothermal low cycle fatigue( LCF). The result shows that the fatigue life of Ti-48 Al-2 Cr-2 Nb alloy in 400℃ ～ 800℃ TMF condition is longer than 400℃ and 800℃ LCF within high strain region. Within low strain region,it is slightly shorter than 400℃ LCF and within the dispersion zone of 800℃ LCF. In this TMF condition,no evidence shows hardening or softening phenomenon. SEM analysis shows that inter-lamellar and inner-lamellar cracking and trans-lamellar tearing can be observed on the fracture surface.更多还原