铝接触反应钎焊的成缝行为

Behavior of Aluminum Contact Reactive Brazing

接触反应钎焊 (CRB)利用中间层材料与母材的冶金反应产生液相实现连接 ,因此可以弥补常规毛细钎焊工艺的某些不足。本文采用Si作为中间层介质进行了铝的接触反应钎焊 ,并得到良好的接头。在此基础上 ,采用经典扩散理论对接触反应钎焊过程中Si中间层的液化及钎缝液相层的形成过程进行了理论分析和计算。结果表明 ,中间层的液化是一个以秒为数量级来衡量的瞬时过程 ;随着中间层厚度的增厚 ,液化时间也逐渐增长 ;而钎焊温度对中间层的液化时间没有明显的影响。同时对钎缝液相层厚度与保温时间之间的定量关系计算结果表明 ,保温时间越长 ,中间层液相的厚度越大 ,并且温度越高 ,增长的趋势越大 ;钎焊温度越高 。

The contact reactive brazing can make joint by the metallurgical reaction between base metal and interlayer, so that it offsets many deficiencies appearing in traditional brazing. A good contact reactive brazed joint of Al was gained by using silicon as an interlayer. The liquefying of Si interlayer and the developing of liquid layer in brazing seam were analyzed and calculated, based on the classic diffusion theory. The results show that the liquefying time of interlayer is so short that it has to be measured in terms of second. The thicker the interlayer is, the longer the liquefying time will be. The brazing temperature had little influence on the liquefying time. The thickness of liquid layer increases with the extending of holding time, and the increasing tendency is stronger when the temperature is higher.