Fine structure at the diffusion welded interface of Fe3Al/Q235 dissimilar materials

Abstract

The interface of Fe3Al/Q235 dissimilar materials joint, which was made by vacuum diffusion welding, combines excellently. There are Fe3Al, FeAl phases and α-Fe (Al) solid solution at the interface of Fe3Al/Q235. Aluminum content decreases from 28% to 1.5% and corresponding phase changes from Fe3Al with DO3 type body centred cubic (bcc) structure to α-Fe (Al) solid solution with B2 type bcc structure. All phases are present in sub-grain structure level and there is no obvious brittle phases or micro-defects such as pores and cracks at the interface of Fe3Al/Q235 diffusion joint.