铝／镀锌钢焊接接头金属间化合物热力学分析

摘要

This research determines an intermetallic compound phase on the interface area of aluminum/galvanized steel plate pulsed DE⁃GMAW⁃welded joints. Based on thermodynamic fundamentals, a calculation model of Gibbs free energy change, formed by the Fe⁃Al⁃Zn compound phase on the interface area of aluminum/galvanized welded joints, was established. The relation between temperature change and the standard Gibbs Free Energy, formed by Fe2 Al5 Zn0.4 intermetallic compound phase on the aluminum/galvanized steel plate welded joints, was obtained. The possible presence of an Fe2 Al5 Zn0.4 intermetallic compound on the welding interface was analyzed and compared with the experiment results. The simulated results show that the established thermodynamic model is reasonable as the Fe2 Al5 Zn0.4 intermetallic compound formed on the interface is basically consistent with the experimental results. It can be deduced that Fe2 Al5 Zn0.4 forms because zinc diffuses into the crystal space of Fe2 Al5 after Fe2 Al5 and FeAl3 are formed.%针对Al／镀Zn钢板Pulsed DE⁃GMAW焊接接头界面区金属间化合物相的确定性研究，在热力学基本定律的基础上，建立铝／镀锌钢板异种金属焊接接头界面Fe⁃Al⁃Zn相形成的吉布斯自由能变化的计算模型，得到Al／镀Zn钢板异种金属焊接接头Fe2 Al5 Zn0．4金属间化合物相形成的标准吉布斯自由能与温度的变化关系，分析界面Fe2 Al5 Zn0．4金属间化合物存在的可能性，并与焊接试验结果进行对比分析。模拟结果表明：所建立的热力学模型是合理的，在界面上形成Fe2 Al5 Zn0．4金属间化合物，与试验结果基本一致，并推论了Fe2 Al5 Zn0．4是在Fe2 Al5与FeAl3形成后，由于Zn扩散进入Fe2 Al5的晶体空位所得到的。