Friction stir welding (FSW)

as an advanced solid-state joining technology

has been widely applied in aerospace and other high-end manufacturing fields. However

the joining of high melting point alloys poses new challenges to the development of FSW. The auxiliary heat source-assisted FSW technique

which utilizes external energy fields

can effectively address the issues encountered during the FSW process of high melting point alloys. This method offers several advantages

including expanding the process window

enhancing mechanical properties

reducing the welding upsetting force

and reducing stir tool wear. This paper summarizes the research progress on various auxiliary heat source-assisted FSW techniques for high melting point alloys

including induction-assisted

laser-assisted

current-assisted

arc-assisted

and backside heating-assisted methods. Significant achievements have been made in these studies

such as increasing heat input

reducing the welding upsetting force

optimizing the microstructure

and improving the mechanical properties of the joints. Furthermore

the future research directions of auxiliary heat source-assisted FSW for high melting point alloys are proposed and discussed.