| 摘要: |
| 采用交流和直流两种方法对AZ31B镁合金进行了电阻点焊,分析了接头的组织形态。结果显示,焊点熔核中心为细小的等轴晶,结晶后的组织为非平衡凝固产生的远离平衡态的组织,在先共晶α-Mg相上析出β-Mg17Al12离异共晶体;直流点焊中加大电极压力使得焊点热影响区组织形态由等轴晶转换为树枝晶;交流点焊规范的改变不引起焊点组织形态的变化,只是影响析出相的数量。 |
| 关键词: 点焊 AZ31B镁合金 组织形态 |
| DOI： |
| 分类号: |
| 基金项目:国家高技术研究发展计划(2002AA33160) |
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| Microstructures analysis of magnesium alloy spot welded joints with AC and DC |
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WANG Ya-rong, ZHANG Zhong-dian, FENG Ji-cai, LIU Hui
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National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China
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| Abstract: |
| AZ31B magnesium alloy was welded by alternating current(AC) and direct current(DC) spot welding machine and microstructure of the joints was studied. The results showed that heat-affected zone(HAZ) in spot welded joint of magnesium alloy appears more narrower in comparison to that of other metals and there are single fine equiaxle crystals in the nugget, of which the structure is β-Mg17Al12 precipitated on α-Mg boundaries induced by non-equibrium freezing. When electrode force increases, equiaxle crystals change into columnar crystals in HAZ of DC spot weld but no morphological differences occur in HAZ of AC spot weld except for amount of precipitated phase. |
| Key words: spot welding magnesium alloy microstructures |
