含有裂纹的Al-Mg合金构件电磁热止裂
来源期刊：中国有色金属学报2013年第1期
论文作者：付宇明 王俊丽 郑丽娟 向龙 张金森
文章页码：29 - 35
关键词：Al-Mg合金；单边裂纹；微观组织；止裂；电磁热效应
Key words：Al-Mg alloy; unilateral crack; microstructure; crack arrest; electromagnetic heating effect
摘 要：利用自行研制的ZL?2型超强脉冲电流发生装置对带有单边裂纹的Al-Mg合金试件进行电磁热止裂实 验，并对放电前后裂纹尖端的微观组织进行对比分析；采用热?电?结构耦合的数值分析方法求得放电后试件的电流密度场、温度场及热应力场；从理论上计算放电后的电热应力强度因子。结果表明：放电电压对止裂效果存在最优值；在适当的强脉冲电流作用下，裂纹尖端在小范围内被瞬间强化加热，随后在极大的热压应力作用下快速冷却，组织发生明显变化，晶粒得到细化，并围绕裂纹尖端形成等值压缩热应力，对裂纹尖端有“夹紧”作用，进而阻止裂纹扩展。
Abstract: Al-Mg alloys specimens with unilateral crack were used to perform electromagnetic heating crack arrest experiment using a self-made ZL?2 super pulse current generation equipment, and the microstructures around the crack tip were analyzed before and after discharge. The current density field, temperature field and thermal stress field were obtained at the moment of the pulse current discharge by the thermal?electrical?structure coupling numerical analysis method. The electrothermal stress intensity factors were theoretically calculated. The results show that there exists an optimal discharge voltage value for the effect of the crack arrest. Under the action of appropriate super pulse current, the crack tip around small-scale is instantly strengthen-heated, followed by rapid cooling under a great thermal compressive stress. The microstructure has an obvious change, and the grains are refined. And the equivalent heat compression stress generates around the crack tip, which has “clamping” role to the crack tip, and then prevents the crack expansion.
付宇明，王俊丽，郑丽娟，向 龙，张金森
(燕山大学 机械工程学院 结构损伤与修复研究所，秦皇岛066004)
摘 要：利用自行研制的ZL?2型超强脉冲电流发生装置对带有单边裂纹的Al-Mg合金试件进行电磁热止裂实 验，并对放电前后裂纹尖端的微观组织进行对比分析；采用热?电?结构耦合的数值分析方法求得放电后试件的电流密度场、温度场及热应力场；从理论上计算放电后的电热应力强度因子。结果表明：放电电压对止裂效果存在最优值；在适当的强脉冲电流作用下，裂纹尖端在小范围内被瞬间强化加热，随后在极大的热压应力作用下快速冷却，组织发生明显变化，晶粒得到细化，并围绕裂纹尖端形成等值压缩热应力，对裂纹尖端有“夹紧”作用，进而阻止裂纹扩展。
关键词：Al-Mg合金；单边裂纹；微观组织；止裂；电磁热效应
FU Yu-ming, WANG Jun-li, ZHENG Li-juan, XIANG Long, ZHANG Jin-sen
(Institute of Structure Damage and Restore, School of Mechanical Engineering,
Yanshan University, Qinhuangdao 066004, China)
Abstract:Al-Mg alloys specimens with unilateral crack were used to perform electromagnetic heating crack arrest experiment using a self-made ZL?2 super pulse current generation equipment, and the microstructures around the crack tip were analyzed before and after discharge. The current density field, temperature field and thermal stress field were obtained at the moment of the pulse current discharge by the thermal?electrical?structure coupling numerical analysis method. The electrothermal stress intensity factors were theoretically calculated. The results show that there exists an optimal discharge voltage value for the effect of the crack arrest. Under the action of appropriate super pulse current, the crack tip around small-scale is instantly strengthen-heated, followed by rapid cooling under a great thermal compressive stress. The microstructure has an obvious change, and the grains are refined. And the equivalent heat compression stress generates around the crack tip, which has “clamping” role to the crack tip, and then prevents the crack expansion.
Key words:Al-Mg alloy; unilateral crack; microstructure; crack arrest; electromagnetic heating effect
