镁合金搅拌摩擦焊接的研究现状与展望

Friction Stir Welding of Magnesium Alloys:A Review

近年来,镁合金在汽车、轨道交通、航空航天等领域的应用需求快速增长,其可靠连接的重要性愈发突出。作为固相焊接技术,搅拌摩擦焊(FSW)对镁合金焊接具有独特优势,因此得到了广泛关注。本文重点综述了镁合金常规对接FSW的研究进展,就焊接工艺、微观组织演化、织构分布特征、接头力学性能及其之间的相互作用机制进行了详细分析与评述。研究表明,不同于铝合金,在变形镁合金FSW时,织构是影响接头性能的关键因素,焊后形成的特殊强织构分布是导致接头难以达到与母材同等强度的主要原因。同时,对其它焊接形式如搭接焊、点焊、双面焊的可焊性及接头性能的影响因素与变化规律进行了讨论,并对镁合金与其它镁合金、铝合金以及钢之间异种焊的可焊性、界面结合机制、接头性能的影响因素及调控方法进行了评述。最后,对镁合金FSW的未来研究方向进行了展望。

In recent years, the increasing application demand for Mg alloys in automobile, rail trans- port, aviation and aerospace industries brings about the growing prominence of seeking reliable tech- niques to join Mg alloys. As a solid state welding method, friction stir welding （FSW） exhibits unique ad- vantages in joining Mg alloys, and thus arouses widespread research interest. This paper emphatically re- viewed the research status of conventional friction stir butt-welding of Mg alloys, and highlighted the weld- ing process, microstructure evolution, texture characteristics, mechanical behavior and their interaction mechanisms. It was indicated that the texture plays a vital role in FSW joint performance of wrought Mg alloys, which is quite different from that in the FSW AI alloy joints. The specific strong texture formed in the weld is the main factor that gives rise to the impediment to achieving equal-strength joints to base ma- terials. At the same time, some focuses like the weldability and the factors that influence joint perfor- mance in other types of FSW like lap welding, spot welding and double-sided welding; the weldability, in- terface bonding mechanism, joint performance and its affecting factors and optimization methods in dis- similar FSW between Mg alloys and other materials like Mg alloys of other grades, AI alloys and steels, were summarized and discussed. Finally, the future research and development directions in FSW of Mg alloys were prospected.