LF6铝镁合金电子束焊接接头的性能与组织初探

分析电子束焊接LF6铝镁合金的焊缝微观组织,研究焊缝中Mg合金元素的烧损现象、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。

A primary study of properties and microstructure of LF6 Al-Mg alloy joint welded by electron beam

Microstructure and burning of Mg element in seam, mechanical properties and hot cracks in joint welded by electron beam were studied. It was showed that fine equiaxial microstructure appeared in seams while cystiform dendrite near by melted line. Evaporation and loss of Mg element was excessive both on the top and in the center of seam. Joint was softened and its strength was 91. 2% of that of the matrix, and both its shrinkage of fractured surface and impact toughness were less than those of the matrix while its elongation was higher than that of the matrix. With appropriate matching parameters, there wouldn' t be hot cracks in seam, and also wouldn' t be lack of fusion or slag inclusion which due to oxidation coating.