Abstract: Micro-connections of copper and copper alloys can be widely used in aviation technology, electronic technology and energy technology, but the material has a high softening temperature, a reduction in frictional heat generation due to the reduction of plastic metal in the weld zone of the sheet, and an increase in the specific surface area of the sheet The problems such as the fast heat transfer speed make the micro friction stir welding(μFSW) process easy to produce welding defects and are not conducive to joint formation. Using 0.6 mm thick ultra-thin plate H62 brass as the research object, carry out butt welding experimental research, in-depth study of the microstructure, mechanical properties and fracture morphology of the joint under different process parameters, and then optimize the process parameters; on this basis, analyze Changes in temperature, axial force and Transverse force during the process. The research shows that the weld seam is well formed after the process optimization, and the maximum tensile strength of the joint reaches 370 MPa, about 92.5% of BM; there is a clear dividing line between HAZ, TMAZ, and NZ at the weld, and NZ is horizontal and vertical. There is non-uniformity in grain shape and size. The highest NZ hardness is about 155.4 HV (approximately 119.5% of BM). Fracture failure easily occurs at the location with the smallest hardness (AS). The failure mechanism is ductile fracture. In the μFSW process, stable axial and Transverse forces can provide appropriate heat input and better extrusion and agitation to obtain a good weld. Through basic research on friction stir welding of high-melting-point copper and its alloy ultra-thin plates, it provides technical support for the promotion of materials for micro-connection technology.

Key words: H62 brass, micro friction stir welding, process analysis, microstructure, tensile strength