Influence mechanism of boron segregation on the microstructure evolution and hot ductility of super austenitic stainless steel S32654

Influence mechanism of B segregation on the microstructure evolution and hot ductility of S32654 at 850-1250 degrees C was systematically investigated through experimental research and theoretical calculation. The results demonstrated that the segregation of B at grain boundary (GB) played different roles in the microstructure evolution and hot ductility at various temperatures. At 850 degrees C, B segregation inhibited Mo segregation at the GB and enhanced the GB cohesion. At 900-950 degrees C, B segregation restricted the diffusion and segregation of Mo to the GB, inhibiting the precipitation of sigma phase. At 10 0 0-1050 degrees C, B segregation accelerated the dislocation accumulation and limited the GB migration, promoting the nucleation and inhibiting the growth of DRX grains. At 1100-1150 degrees C, B has little effect on the DRX due to sufficient energy supply by higher temperature. Under the above beneficial effects of B, the hot ductility of S32654 was improved to varying degrees at 850-1150 degrees C. However, as the temperature increased to 1200-1250 degrees C, B segregation decreased the solidus temperature and enhanced the liquefaction cracking tendency, resulting in a deterioration of the hot ductility. (c) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

The influence mechanism of B segregation on the microstructure evolution and hot ductility of S32654 at 850-1250 degrees C was systematically investigated. B segregation played different roles in Mo segregation, dislocation accumulation, and grain boundary migration, affecting the microstructure evolution and hot ductility of the material.