Effect of heat treatment on microstructure near diffusion bonding interface of Fe_3Al/18-8 stainless steel

摘要

The microstructure of Fe_3Al/18-8 diffusion bonding joint after heat treatment was analysed by metalioscopy, scanning electron microscopy and X-ray diffraction. The experimental results indicated that the size of grains near the Fe_3Al/18-8 diffusion interface was decreased significantly and the microstructure near the interface became homogeneous. The precipitations also became tiny with regular shape and were distributed evenly at the interface region. The microhardness of the Fe_3Al/18-8 diffusion bonding joint was decreased and no brittle phase with high microhardness existed near the interface after heat treatment. The suitable parameters of heat treatment were: heating temperature T=800 deg C, holding time t=30 min, furnace cooling to 700 deg C then air cooling.