Interfacial microstructure evolution behavior during plastic deformation bonding of GH4065A superalloy

Abstract

To clarify the evolution of the interfacial microstructure of GH4065A superalloy during plastic deformation bonding， the GH4065A superalloy is bonded under temperatures of 1050-1110 ℃ with the pressure of 20-40 MPa and a time range of 20-35 min. OM，SEM， and EBSD were employed to characterize the special positions between bonding regions and unbinding regions to investigate further the influence of plastic deformation bonding parameters（bonding temperature，holding time，and bonding pressure） on the microstructural evolution of the interface.This study focuses on the nucleation of new recrystallization grains in the bonding area and the healing of the original interface. The results show that increasing the bonding temperature， pressure and the holding time will facilitate the healing of the interface. but at the same time， it will also prompte the coarsening of the grains simultaneously. The joint obtained under 1080 ℃，30 MPa，30 min has uniform microstructure and no obvious defects， exhibiting an excellent metallurgical bonding effect.The results of EBSD show that the discontinuous dynamic recrystallization characterized by strain-induced grain boundary bulging is the dominant mechanism， and continuous dynamic recrystallization characterized by subgrain progressive rotation occurs in the bonding process. Moreover， the dynamic recrystallization（DRX）nuclei will grow toward the interface with ongoing deformation， contributing to the healing of the original interface.The metallurgical bonding caused by plastic deformation bonding mainly experiences three stages： initial contact， nucleation and grain growth， and joint formation.

Keywords

• gh4065a superalloy
• plastic deformation bonding
• interfacial microstructure
• dynamic recrystallization
• interfacial healing