Investigation of microstructure, texture, and mechanical properties of FeCoNiCrMn high entropy alloy during drive friction welding

FeCoNiCrMn high-entropy alloy (HEA) with FCC structure was welded by continuous drive friction welding. The microstructure and mechanical properties of welding joints were investigated using OM, XRD, EBSD, TEM, microhardness, and tensile tests. The microstructure of welding joints samples consist of three zones: the weld zone (WZ), the thermal-mechanically affected zone (TMAZ) and the base metal zone (BM). The microstructure of WZ is consistent with that of BM, which is a single FCC solid solution. Discontinuous dynamic recrystallization (DDRX) and twin-induced dynamic recrystallization (TDRX) mainly occur in WZ and TMAZ. The hardness of TMAZ is significantly increased and higher than that in WZ and BM; the hardness of WZ is slightly higher than that of BM. The increase of the hardness is related to grain refinement. The tensile strength and uniform elongation of the joint samples are increased by 4.2% and 31% respectively compared with the results of the base metal. The results exhibited ductile fracture.