Interface characteristics in diffusion bonding of Fe 3Al with Cr18-Ni8 stainless steel

Abstract

Fe 3Al and Cr18-Ni8 stainless steel were diffusion-bonded in vacuum and a Fe 3Al/Cr18-Ni8 interface with reaction layer was formed. Microstructure in the reaction layer at Fe 3Al/Cr18-Ni8 interface was analyzed by means of scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA). The growth of reaction layer with heating temperature ( T) and holding time ( t) was researched. The results indicate that FeAl, Fe 3Al, Ni 3Al, and α-Fe (Al) solid solution are formed in the reaction layer. These phases are favorable to promote the element diffusion and to accelerate the formation of the reaction layer at Fe 3Al/Cr18-Ni8 interface. The growth of reaction layer obeys the parabolic law and its thickness ( X) is expressed by X 2 = 7.5 × 10 −4 exp ( − 83.59 / R T ) ( t − t 0 ) .