升温速率对Al-Si-Cu基钎料在6063铝合金表面润湿的影响

Influence of Heating Rate on Wettability of Al-Si-Cu-based Brazing Alloy on 6063 Aluminum

基于Al-Si-Cu基低熔点钎料在6063铝合金板上的铺展试验,测试了不同钎剂条件下升温速率对钎料润湿性的影响,并对影响机理进行了分析探讨.铺展试验结果表明:在不同氟化物钎剂条件下,快速升温(约18℃/min)时,钎料的铺展面积是缓慢升温(约1.5℃/min)时的4倍左右,铺展形貌也有较大差异.研究发现,升温速率主要通过影响钎剂作用效果、钎料扩散及传质过程等影响钎料的润湿.长时间加热导致钎剂去膜活性不稳定,钎料表面产生高温氧化膜是造成缓慢升温钎料润湿性差的主要原因.另外,升温速率作为温度变化信号,在动力学方面影响着钎料铺展速率及钎料钎剂间的传质速率等,从而影响钎料的润湿.

The spreading test of Al-Si-Cu based brazing alloy on 6063 aluminum was conducted and the influence of heating rate on wettability of brazing alloy with different flux-assisted was analyzed.Experimental results show that the spreading areas of brazing alloy on 6063 aluminum with rapid heating rate(about 18 ℃/min) was 4 times more than that with slow heating rate(about 1.5 ℃/min),and the morphology of spreading was also evidently different.The wettability was affected by the heating rate through the weakening effect of the flux and the speed of spreading,mass transferring and slowing down of the diffusion process.The most important cause for weak wettability is that the flux activity for removing oxide film were weakened in slowly heating rate and that the thick oxide film appeared at high temperature.In addition,as a signal of temperature variation,in kinetics,the heating rate influences the spreading and mass transfer rate among brazing alloy,flux and substrate,which plays an important role in wettability of brazing alloy.