对固溶+人工时效(T6)处理的挤压变形Al-0.8%Mg-0.6%Si,Al-0.8%Mg-0.6%Si-0.2%Sc和Al-0.8%Mg-0.6%Si-0.3%Er合金进行了低周疲劳试验,探讨了合金的低周疲劳变形和断裂行为。结果表明,低周疲劳变形期间,含Sc,Er合金可以呈现循环应变硬化、循环应变软化和循环稳定;添加稀土元素Sc可提高合金的循环变形抗力,且含0.2%Sc的合金在疲劳变形期间发生双系滑移;含Sc,Er合金的弹性应变幅和塑性应变幅与断裂时的载荷反向周次的关系可分别用Basquin和Coffin-Manson公式来描述,其中Al-0.8%Mg-0.6%Si-0.2%Sc合金的塑性应变幅与断裂时的载荷反向周次之间呈双线性关系;含Sc,Er合金的疲劳裂纹均是以穿晶方式萌生于试样表面,并以穿晶方式扩展。 Al-0.8% Mg-0.6% Si, Al-0.8% Mg-0.6% Si-0.2% Sc and Al-0.8% Mg-0.6% Si-0.3% Er alloy was subjected to low cycle fatigue test to investigate the low cycle fatigue deformation and fracture behavior of the alloy. The results show that during the low-cycle fatigue deformation, the alloy containing Sc and Er can exhibit cyclic strain hardening, cyclic strain softening and cyclic stability; addition of rare earth Sc can improve the cyclic deformation resistance of the alloy, and the alloy containing 0.2% Sc during fatigue deformation The slip of the double system occurs. The relationship between elastic strain amplitude and plastic strain amplitude of Sc, Er alloy and load reverse cycle at fracture can be described by Basquin and Coffin-Manson formulas, respectively. Al-0.8% Mg-0.6 The plastic strain amplitude of% Si-0.2% Sc alloy has a bilinear relationship with the load reverse cycle at fracture. The fatigue cracks of Sc and Er alloy are initiated by the transgranular method on the surface of specimens Transmutation way to expand.