论文部分内容阅读
镁合金具有质量轻、拉伸强度高和减振能力强的优点,钢一直在制造业中占主导地位。镁钢异种材料的连接,可以实现汽车构件的轻量化设计,对节能减排有着重要的积极意义。采用KDWJ-17型三相次级整流电阻焊机对2.0 mm厚的AZ31B镁合金和1.0 mm厚的SPHC镀锌钢板进行电阻点焊焊接试验,利用QUANTA200型扫描电子显微镜(SEM)分析接头各区域的组织结构和成分分布,并对接头化合物做热力学分析,研究AZ31B镁合金和SPHC镀锌钢点焊接头中心界面化合物的形成机制。研究结果表明:接头处Fe_2Al_5化合物是形成高强度镁合金与镀锌钢板电阻点焊接头的主要原因;结合Fe-Al二元相图和热力学分析计算,在镁合金和镀锌钢板电阻点焊接头中,Fe_2Al_5在可直接生成的Fe-Al系化合物中为接头相结构的最有利生成相;Fe_2Al_5的结构单元总成键能力在Fe-Al系化合物中其化合物保持自身结构稳定性的能力最强。
Magnesium alloy has the advantages of light weight, high tensile strength and strong vibration damping capability, and steel has been the dominant manufacturing industry. Magnesium steel dissimilar materials connection, can achieve lightweight car components design, energy saving has an important positive significance. Resistance welding was carried out on 2.0 mm thick AZ31B magnesium alloy and 1.0 mm thick SPHC galvanized steel using KDWJ-17 three-phase secondary rectifier resistance welding machine. The joints were analyzed by QUANTA200 scanning electron microscope (SEM) The microstructure and composition distribution of the joints were investigated. The thermodynamic analysis of the joint compounds was carried out to study the formation mechanism of AZ31B magnesium alloy and SPHC galvanized steel spot-welded joint center interface compounds. The results show that the Fe_2Al_5 compound at the joint is the main reason for forming the resistance spot welded joints of high strength magnesium alloy and galvanized steel. Based on the binary phase diagram of Fe-Al and the thermodynamic analysis, , Fe 2 Al 5 is the most favorable phase for the linker structure in the Fe-Al compounds that can be directly formed. The total bonding ability of Fe 2 Al 5 in the Fe-Al compounds is the strongest for their compounds to maintain their structural stability .