AgCu28钎料钎焊无氧铜晶界渗透行为分析

使用AgCu28钎料多次钎焊无氧铜和其他材料时，极易造成无氧铜母材性能下降.为解决此问题，针对采用AgCu28钎料焊接的无氧铜-无氧铜、无氧铜-镀镍不锈钢和无氧铜-蒙乃尔3种钎焊接头的微观组织进行观察，发现无氧铜-无氧铜的钎焊接头中钎料与焊缝结合紧密，接头组织良好；而无氧铜-镀镍不锈钢和无氧铜-蒙乃尔的钎焊接头中AgCu28钎料沿着无氧铜晶界进行扩散，即出现明显的晶界渗透现象.成分检测表明，含Ni母材中的Ni元素在钎焊过程中快速溶解进钎料，经分析认为Ni元素在钎料中的溶解是导致钎料对无氧铜产生晶界渗透的主要原因. 

Grain boundary penetration behavior analysis of OFC brazed with AgCu28 brazing filler

Repeated use of eutectic AgCu28 solder can cause performance degradation in the base material due to grain boundary penetration. To gain further understanding of this phenomenon, thus providing comprehensive data and technical guidance for greater reliability during production of vacuum devices, the microstructure and composition of oxygen-free copper (OFC)-Nickel-plated steel, OFC-Monel, and OFC-OFC brazed joints using AgCu28 brazing filler was observed through SEM and optical microscopy. Results show that the brazing filler in the OFC-OFC brazed joints is securely soldered to the joints' microstructure, and the microstructure is very condensed. However, the filler in the brazed joints of OFC-Nickel-plated steel and OFC-Monel diffuses along the OFC boundary, showing very apparent grain boundary penetration in the brazed joints. Ingredient analysis show that during soldering, the Ni element in Ni-containing base metal dissolves into the brazing filler rapidly. It is surmised that the dissolving of Ni element in the brazing filler is the main reason leading to grain boundary penetration.