Recent progress on external magnetic field assisted laser welding: mechanism, effect and technology

External magnetic field assisted laser welding (MALW) is proved to be effective in improving welding stability, inhibiting welding defects and enhancing mechanical properties. Large numbers of researches are focusing on this technology and aiming at revealing the mechanisms and effects of magnetic field on molten pool dynamics, weld appearances and microstructures. The MALW is an advanced welding method being potential for industrial extension due to its flexible and cost-effective features. However, a comprehensive summarization on recent researches and the latest achievements is lacking. This review is significant in developing advanced welding techniques and promoting application of magnetic field in materials processing. This paper reviews the recent progress of magnetic field assisted laser welding in three aspects: (i) Mechanisms, the fundamental interaction mechanisms between magnetic field and fluid flow basing on magnetohydrodynamics (MHD); (ii) Technologies, the technologies developed basing on magnetic field assisted laser welding; (iii) Effects, the effects of magnetic fields on defects, microstructures and properties. Finally, the main conclusions of current researches and potential prospects are discussed to supply useful directions for future exploration in related fields.