Effect of re-heating on microstructures near Fe₃A1/18-8 diffusion bonding interface

There unevenly distributed second-phase precipitations at the Fe₃A1/18-8(stainless steel) diffusion bonding interface directly.Especially,the continuous precipitation groups at the boundary could induce welding cracks,which was the main factor caused the failure of the Fe₃A1/18-8 diffusion-bonded joint.The Fe₃A1/18-8 diffusion-bonded joint was re-heated and the precipitation and phase constituent of the interface were analysed by means of scanning electron microscope,energy dispersive spectrum and X-ray diffraction.The results indicated that the precipitation distributs evenly at the Fe₃A1/18-8 diffusion bonding interface due to the effect of re-heating and the precipitation becomes tiny and regular.The continuous precipitation groups are liquated.The microhardness near the Fe₃A1/18-8 diffusion bonding interface decreases and there are no higher-microhardness brittle phases after re-heating.