(1. 北京工業(yè)大學(xué) 汽車結(jié)構(gòu)部件先進(jìn)制造技術(shù)教育部工程研究中心，北京 100124；
2. 北京新能源汽車股份有限公司，北京 100176)
摘 要: 采用載流攪拌摩擦焊方法對(duì)6 mm厚AA2219鋁合金板進(jìn)行了不同脈沖電流大小的對(duì)接焊實(shí)驗(yàn)，研究焊接接頭顯微組織形貌和力學(xué)性能，結(jié)合斷口宏觀形貌及不同區(qū)域的硬度分布趨勢(shì)，揭示電流對(duì)接頭性能的影響。結(jié)果表明：隨著電流增加，熱輸入增高，晶粒動(dòng)態(tài)再結(jié)晶區(qū)域增多，接頭抗拉強(qiáng)度和斷后伸長(zhǎng)率提升，拉伸試樣斷裂均發(fā)生在前進(jìn)側(cè)攪拌區(qū)和熱機(jī)影響區(qū)的交界處。通過(guò)研究斷口微觀結(jié)構(gòu)發(fā)現(xiàn)，載流接頭更佳，增強(qiáng)了接頭的韌性斷裂。對(duì)焊接接頭橫截面硬度進(jìn)行研究，其硬度變化趨勢(shì)呈現(xiàn)“V”分布，焊核區(qū)硬度提高。焊縫中不同區(qū)域受攪拌針作用和熱量分布情況不同，導(dǎo)致焊縫中析出相分布不同，影響了接頭硬度，改善了焊接接頭力學(xué)性能。
關(guān)鍵字: 2219鋁合金；載流攪拌摩擦焊；顯微組織；力學(xué)性能
（1. Beijing University of Technology, Advanced Manufacturing Technology of Automobile Structural Components Engineering Research Center of Ministry of Education, Beijing 100124, China;
2. Beijing New Energy Automobile Co., LTD., Beijing 100176, China）
Abstract:The butt welding experiments of 6mm thick AA2219 aluminum alloy plates were carried out by friction stir welding with different pulse currents. Mechanical properties, microstructure, fracture macroscopic morphology and hardness distribution trend of the welded joints were studied. The effect of current on the performance of the joint was revealed. The results show that the dynamic recrystallization region, the tensile strength and elongation of the joint increase with increasing the current value and the heat input. The tensile samples fracture at the junction of weld nugget zone and thermo-mechanically affected zone at the advancing side. Through the study of fracture microstructure, it is found that the electrically assisted joints are better and the ductile fracture of the joints has enhanced. The cross section hardness of the welded joint was studied. The hardness change trend has a “V” shape distribution, and the hardness of weld nugget zone increases. The effect of pin on different areas of the weld is distinct with different heat distribution, resulting in different distributions of precipitates in the weld, which affects the hardness of the joints and improves the mechanical properties of the welded joint.
Key words: 2219 aluminum alloy; electrically assisted friction stir welding; microstructure; mechanical property
