稀土元素在铝合金真空钎焊中的作用

研究了真空钎焊时在钎料中加入微量稀土元素Ｌａ、Ｃｅ，能显著提高Ａ１－Ｓｉ基钎料对ＬＤ３０铝 合金的润湿性和真空钎焊接头质量；明显改善钎缝微观组织，使晶粒细化，并使中间相分布更均匀， 改变第二相ＣｕＡｌ_２、Ｍｇ_２ Ｓｉ的网状分布，使之变薄变细；促进铝合金基体与钎料中合金元素的相互 扩散和均匀分布；从而使钎焊接头强度明显提高．

Effects of rare earth element on LD30 vacuum brazimg

By adding rare earth elements of La and Ce into the brazing filler metals in vacuum brazing process, the wetting properties of the brazing filler metals with the AI-Si base aloy LD30, the microstructure of the welding line and the mechanical properties of brazing joints can be greatly improved. The crystal grains also tend to be fine and metallic phase are mere homogenized. The network structures of second phases CuAl_1Si could be changed and tend to be more thin and fine. It promoted the diffu sion of the atoms between the Al base alloy and the brazing filler metals, which results in uniform distribution of these elements and raises the strength of brazing joint.