铝合金储能焊快速凝固接头组织分析
Analysis on Microstructure of Rapidly Solidified Joint of LF2 Aluminum Alloy Welded by Capacitor Discharge
徐 峰
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作者单位：陕西理工学院 材料科学与工程学院，陕西 汉中 723003
中文关键字：储能焊； LF2铝合金； 接头组织
英文关键字：capacitor discharge welding; LF2 aluminum alloy; joint microstructure
中文摘要： 采用微型储能焊机对厚度为0.4 mm的LF2铝合金薄板进行快速凝固点焊，研究分析了接头组织形貌和形成机理。结果表明，储能焊能够实现LF2铝合金薄板的快速凝固焊接，焊接接头由熔核区、熔合区和热影响区组成。极大的冷却速率使得接头组织瞬间形核并快速生长，形成组织细小致密具有快速凝固特征的焊接接头。焊接裂纹是LF2铝合金储能焊主要焊接缺陷。对焊接裂纹机理分析发现，铝合金线膨胀大导致焊接应力产生是形成焊接裂纹的主要原因。
英文摘要：LF2 aluminum alloy with 0.4 mm thickness was performed using a micro-type capacitor discharge welding machine. The structure characteristic and joining mechanism of the welding joint was investigated. The results show that the rapidly solidified welding of aluminum alloy can be realized by capacitor discharge welding, the joint microstructure consists of nugget zone, semi-melt zone and heat affected zone. Due to very high cooling rate, the nugget structure rapidly nucleates and grows. The refined microstructure of the nugget with rapidly solidified characteristic is formed. The main welding defect of the alloy is crack. The formative mechanism of the crack is the welding stress produced by the big linear expansibility of the alloy.