LF6铝镁合金电子束焊接

A Primary Study of Properties and Microstructure of LF6 Al-Mg Alloy Joint Welded by Electron Beam

研究了焊缝中合金元素Mg的烧损现象、焊接接头的力学性能和焊接热裂纹等问题。结果表明,电子束焊接LF6铝镁合金,其焊缝组织为微细等轴晶,熔合线附近为胞状树枝晶;Mg合金元素在焊缝上部和中心区有较大的蒸发损失;焊接接头存在一定的软化,其抗拉强度为母材的91·2%,除延伸率比母材高外,断面收缩率和冲击韧性值与母材相比均有所降低;在合适的参数匹配下,焊缝中不会出现热裂纹以及氧化膜所导致的熔合不良与夹渣等问题。

Microstructure and burning of Mg element in seam, mechanical properties and hot cracks in joint welded by electron beam were studied. It was shown that fine eQuiaxial rnicrostructure was formed in seams while cystiform dendrite near the melted line. More Mg element was lost by evaporation on the top and in the center of seam. The strength at welded joint was 91.2% of that of the matrix because of the softening effect, and there were lower shrinkage of fractured surface and impact toughness but higher elongation than in the matrix. With appropriate matching parameters, no hot cracks, lack of fusion or slag inclusion due to oxidation coating was formed in weld seam.