铬青铜与不锈钢瞬间液相扩散焊接界面行为

Interface behavior of TLP between chromium-copper alloy and stainless steel

为了掌握铜合金与不锈钢的连接机理,为工程应用提供技术指导,对铬青铜和不锈钢异种材料扩散焊接进行了研究,对不同厚度的银、铜镀层在不同焊接条件(焊接温度和时间)下的试验进行了分析,利用金相显微镜、扫描电镜以及能谱分析仪分别研究了宏观爆破压力和微观组织结构对焊接质量的影响,对焊接过程发生的冶金结合机理和元素的扩散形式进行了探讨.结果表明,将银、铜镀层的厚度控制在一定范围内,选取950～970℃保温15～60min,焊缝强度可以达到150MPa以上,界面没有脆性相产生.焊缝界面主要表现为铜的扩散、银的反应扩散及TLP过程、银的熔态扩散、铬的聚集析出、镍的网状析出以及柯肯达尔(Kirken-dall)效应等微观特征.

In order to grasp the link mechanism of copper alloy and stainless steel and provide technical guidance for engineering applications, the diffusion bonding between chromium-copper alloy and stainless steel was researched. Effects of blasting pressure and microstructure on the welding performance at different welding temperatures and time were studied with different coating thickness for both copper and silver. The metallurgy combinative mechanism of elements on the diffusion boundary and their diffusion behaviors were investigated with microscope, SEM and EDS. Experimental results show that the intensity of the junction can reach 150 MPa under the conditions that the coating thickness of both copper and silver is in a limited range, the temperature is 950 -970 ℃, and the heat preservation time is 15 -60 minutes. At the same time, few embitterment phases can be precipitated. The mierostructure characters on the junction include the copper diffusion, reacting diffusion of silver and TLP, melting diffusion of silver, chromium evaporation, net-evaporation of nickel, and Kirkendall effect.