纯铁钎焊凝固过程的模拟计算

Analog computation of solidification process when brazing pure Fe

采用BNi-2+40%BNi-5的混合钎料对纯铁进行真空钎焊,运用金相分析、扫描电镜分析(SEM)、能谱分析(EDS)并配合Thermo-Calc及Dictra软件计算对钎焊接头显微组织、钎缝成分分布、相组成和元素扩散情况进行了研究.结果表明,纯铁钎缝主要由γ-Ni固溶体和Cr-B金属间化合物组成;通过Thermo-Calc和Dictra软件计算,温度冷却至1 173 K时钎料仍没有凝固完毕,凝固过程中发生了共晶反应,此时相组成及元素扩散行为的计算结果与试验结果基本吻合,可在一定程度上指导钎焊新工艺的制定.

In order to study the influence of Fe element on the microstructure of brazing joints of stainless steel using nickel-based filler metal,vacuum brazing of pure Fe was performed using BNi-2+40%BNi-5 composite filler in the paper.The microstructure,the element distribution,the phase composition and the element diffusion of the brazed joint were investigated by using metallographic analyzer,scanning electron microscopy(SEM),energy dispersive spectrometry(EDS) and computing Thermo-Calc and Dictra software.The results indicated that the joint of pure Fe were composed of γ-Ni solid solution and Cr-B intermetallic compound.The results which were calculated by Thermo-Calc and Dictra software showed that metallurgical solidification had not been finished when the temperature was cooled down to 1 173 K and eutectic reaction happened during this phase.This moment the computed results of the phase composition and the element diffusion behaviors are basically consistent with expermental results,which can be used for making the new technology of brazing.