镀锌量对低合金钢/5052铝合金感应静压焊接头微观组织与力学性能的影响

Effects of Amount of Galvanization on Microstructure and Mechanics Properties of Joints Made by Induction-pressure Welding of Low Alloy Steel/5052 Aluminum Alloy

运用感应静压焊接技术制备了三种不同镀锌量低合金钢与铝合金的搭接接头,研究不同镀锌量对感应静压焊接头界面连接状态、微观组织形貌以及力学性能的影响规律。结果表明,三种不同镀锌量搭接接头连接界面较平直,连接质量良好。接头中间界面区由靠近钢侧的Fe_(2)Al_(5)和靠近铝侧的FeAl_(3)组成。对比三种不同镀锌量接头微观组织发现,Zn元素能改善钢铝界面初始润湿机制,强化低合金钢与铝合金之间的连接效果,提高搭接接头力学性能。当使用镀锌量为140 g/m~2的低合金钢板进行焊接时,在焊趾位置发现了明显的富锌区缺陷,导致接头剪切性能急剧下降。低合金钢板与铝合金的搭接接头的剪切性能随着镀锌量的增加呈现出先提高后降低的趋势,挑选厚度适中的镀锌层对提高接头力学性能具有重要意义。

Three lap joints of low-alloy steel plates with different galvanizations and aluminum alloys were prepared using IPW technique.The effects of different amounts of galvanization on the interfacial connection state,microstructure characteristics and mechanics properties of the joints were studied.The results show that the connection interfaces of the three different amount of galvanization joints are straighter and the connection quality is good.The middle interface area of the joint consists of Fe_2Al_5 near the steel side and FeAl_3 near the aluminum side.By comparing the microstructure and morphology of the joints with three different amount of galvanization,it is found that Zn element may improve the initial wetting mechanism at the steel-aluminum interfaces,strengthen the connection effect between aluminum alloy and low-alloy steel,and improve the mechanics properties of the lap joints.When welding with a low alloy steel plate with a galvanization of 140 g/m~2,a significant zinc-rich zone defect is found at the weld toe position,resulting in a sharp drop in the shear properties of the joints.The shear properties of lap joints of low-alloy steel sheets and aluminum alloys show a trend of increasing and then decreasing with the amount of galvanization,and it is important to select a moderate thickness of galvanization to improve the mechanics properties of the joints.