【摘要】 研究了应力幅值对Al-Zn-Mg合金的疲劳损伤行为的影响。对不同应力幅值下Al-Zn-Mg合金的微动疲劳寿命以及微动疲劳损伤特性进行了研究。采用宏观力学试验与微观分析相结合的方法,对Al-Zn-Mg合金的微动疲劳机理进行了探讨。结果表明,Al-Zn-Mg合金的微动疲劳寿命随应力幅值的增加呈非线性降低;Al-Zn-Mg合金的微动疲劳寿命与位移幅度值具有一定的关系。微动疲劳损伤区存在微动磨损和裂纹萌生及扩展两种破坏机制,随应力幅值的变化而产生竞争关系。微动疲劳裂纹源均形成于微动斑边缘,微动能促使微动疲劳裂纹萌生和加速扩展。更多还原

【Abstract】 Effect of stress amplitude on fretting fatigue damage behavior of Al-Zn-Mg alloy was studied.Fretting fatigue tests were designed to determine the influence of stress amplitudes on fretting fatigue lives and fretting fatigue damage characteristics.Based on the macroscopic and microscopic experimental results of fretting fatigue of Al-Zn-Mg alloy,fretting fatigue characteristic and damage mechanism of Al-Zn-Mg alloy were intensively analyzed.Results show that stress amplitude affects the fretting fatigue performance significantly.With stress amplitude increasing,fretting fatigue lives are reduced nonlinearly and of certain relationship with the displacement amplitudes.There are two failure mechanisms,i.e.fretting wear and crack initiation along with propagation at the fretting fatigue damage zone,which are in competition relationship with stress amplitudes changing.Fretting fatigue crack initiates at the edge of fretting fatigue zone and fretting can accelerate fretting fatigue crack initiation and propagation.更多还原