Cu-P钎料真空钎焊紫铜的钎焊后扩散及组织分析

Diffusion and microstructure analysis of copper vacuum brazing with Cu-P filler

钎焊后扩散处理能提高硬钎焊接头质量、消除接头缺陷,采用管–板接头设计研究了钎焊后扩散处理对Cu-P钎料真空钎焊紫铜接头组织性能的影响,利用电镜、能谱、拉脱等方法,研究了扩散处理对钎焊接头组织和性能的影响规律.结果表明,钎缝接头组织主要由铜基固溶体和Cu-P二元共晶组织组成,钎焊后扩散处理使得钎缝中心界面宽度明显变窄,钎焊后扩散使得钎缝组织成分更加均匀,而微量P元素又可细化紫铜晶粒,减少Cu3P脆性相生成,铜基固溶体增多,铜磷二元共晶逐渐减少;拉脱试验还发现经过扩散处理后接头抗拉强度由原来143 MPa上升至171 MPa,且接头脆硬倾向变小.

The diffusion treatment after vacuum brazing is an important technique to improve the quality of brazing joint and eliminate the defects of joint.Cu-P based filler was carried out by studying effects of diffusion treatment after vacuum brazing using a tube-sheet joint,and the influence of diffusion treatment on brazing joint was investigated by means of electron microscope,energy spectrum analysis and tensile force test.The results showed that the brazing joint structure was composed by copper-based solid solution and copper-phosphorus binary eutectic,and the brazing seam center interface areas became evidently more narrowed after brazing diffusion treatment,which makes brazing organization more and more uniformly.Meanwhile,small amounts of phosphorus can refine the copper grain;as a result,the brittleness of Cu3P decreased and copper phosphorus binary eutectic was gradually reduced.Tensile force test found that tensile strength was up to 171 MPa on diffusion-treated than 143 MPa with nondiffusion,and the plasticity became better.