铜铝异质金属火焰钎焊试验研究

Experimental study on the dissimilar metals of copper and aluminum by means of torch brazing

选用AlSiLaSr、锌铝8213、8515三种钎料研究LF6/Cu火焰钎焊。并通过金相显微镜,扫描电子显微镜(SEM)和X射线衍射仪(XRD)对焊后接头进行金相分析,形貌和物相分析。结果表明:8515钎料的钎焊工艺效果较好,焊缝中的Cu5Zn8相、α-Al相和β-Cu相较多,Cu9Al4相和CuAl相次之,AlCu5较少。钎料中加入少量的稀土元素不仅可以细化焊缝中的晶粒,而且可以使焊缝的组织更加致密。焊缝中大量的脆性相的产生,导致过渡区和焊缝中心区的硬度明显升高,同时也导致接头的强度降低。要获得较好的接头,必须调整焊接的工艺参数,保证钎缝中的脆性相呈不连续分布或弥散状态存在。

It was chosen that three solders of AlSiLaSr,Zn-Al solder 8213 and 8515 to braze Cu/LF6 by means of the flame.And through optical microscope,scanning electron microscopy（SEM） and X-ray diffraction（XRD） the joints after welding were carried out the metallographic analysis,morphology and phase analysis.The results showed that：the brazing effect of Zn-Al solder 8515 was best in three solders.There were more Cu5Zn8 phase,α-Al phase and β-Cu phase,Cu9Al4phase and CuAl phase followed,and less AlCu5 phase in the brazing seam region.A small amount of rare earth elements in the filter metal can not only refine the grain in the weld,and the microstructure in the welding can be more compact.The arising of a large number of brittle phases in the brazing seam region resulted in that the hardness of the central area and the transition zones was significantly higher than that of the base metal,while the strength of the joint decreased.To get a better joint,welding process parameters should be adjusted to ensure that the brittle phases in the brazing seam brazing region are a discontiguous distribution or an existence in the form of the dispersion state.