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本文从材料的循环响应水平、疲劳开裂阻力、疲劳耗散能量等角度，对可能用于我国高速客车车体的３个系列５种典型国产铝合金的循环特性与疲劳抗力进行了分析和讨论。建立和描述了疲劳断裂能与寿命的关系。阐述了观察到的两种７０００系列合金在小塑性应变幅下循环软化，而在大塑性应变幅下循环硬化的现象。疲劳试验结果还显示了强化机制的影响，证实了时效强化合金疲劳寿命曲线的双斜率的存在。
In this paper, the cycle characteristics and fatigue resistance of three typical domestic aluminum alloys of three series which may be used in high-speed passenger car bodies in China are analyzed and discussed from the perspective of material’s cyclic response, fatigue cracking resistance and fatigue dissipation energy. The relationship between fatigue fracture energy and life span is established and described. The observed phenomena of the two 7000 series alloys that cycle soften at a small plastic strain amplitude and cycle at a large plastic strain amplitude are described. The fatigue test results also show the influence of the strengthening mechanism, confirming the existence of the double slope of the fatigue life curve of the aging-strengthened alloy.