稀土元素在LD30铝合金真空钎焊中的作用

研究了添加La和Ce的Al-Si基钎料真空钎焊LD30铝合金接头的力学性能，微观组织形貌和EDS，并与未添加稀土元素的Al-Si基钎料真空钎焊接头进行对比。结果表明，添加稀土元素的LD30铝合金真空钎焊接头抗拉强度为288MPa，达母材抗拉强度的97．6％，明显高于未添加稀土的LD30合金真空钎焊接头。其机制在于La,Ce能够明显提高Al-Si基钎料与LD30铝合金的润湿性能，改善LD30铝合金真空钎焊接头焊缝及其基体中杂质元素的分布，促进钎料和母材中各元素的均匀扩散，从而提高真空钎焊接头的力学性能。

Influences of Rare Earth Elements in LD30 Aluminum Alloy Vacuum Brazing

Mechanical properties, microstructures and EDS of LD30 alumina alloy vacuum brazing tie in welded with La and Ce added Al Si based welder were all studied. The results show that stretch strength can be highly improved up to 288 MPa, i.e., 97.6 percent of that of raw material, which is greatly higher than that of LD30 alumina alloy vacuum brazing tie in welded with non rare earth elements. According to the study, the reason is that rare earth elements La and Ce can not only improve the wetting property of Al Si based welder, vacuum brazing seam quality and impurity elements distribution, but also promote all elements in the welder and LD30 to diffuse uniformly, and thus the mechanical properties of the LD30 tie in are increased.