Na对Al—Mg—Li合金焊缝金属韧性的影响

EFFECT OF Na ON PLASTICITY OF Al─Mg─Li ALLOY WELD METAL

研究了ＴＩＧ焊接时微量杂质元素Ｎａ对０１４２０Ａｌ－Ｍｇ－Ｌｉ合金焊缝金属力学性能的影响．Ｎａ含量小于２０μｇ／ｇ时，焊缝金属不发生脆化，含量达到５０μｇ／ｇ时，焊缝强度稍有下降，塑性急剧降低用电子探针分析发现Ｎａ在焊缝枝晶界偏聚．

The effect of trace impurity element Na on the mechanical properties of 01420 Al-Mg-Li al loy weld metal by TIG process was investigated. The weld metal is not brittle at Na content less than 20μg g-1. When Na content was increased to 50 μ g' g-1, the strength of weld metal only decreased slightly, but the plasticity decreased sharply. From the analysis of electron probe, it could be found that the Na segregated to dendrite boundaries in weld metal.