To study the effects of rare earth(RE)and Ti on the solidification micros true ture of high borated stainless steels,1.6 wt%B stainless steel doped with RE and2.1 wt%B stainless steel doped with Ti were prepared by in...To study the effects of rare earth(RE)and Ti on the solidification micros true ture of high borated stainless steels,1.6 wt%B stainless steel doped with RE and2.1 wt%B stainless steel doped with Ti were prepared by ingot casting,respectively.The solidification microstructure of researched steels was characterized in detail.The modification mechanism was clarified based on the heterogeneous nucleation theory and the thermodynamic calculation.The solidification microstructure of 1.6 wt%B and 2.1 wt%B stainless steels was characterized by the continuous and network-like eutectic borides around the matrix grains.It was found that the fine RE compounds could act as the heterogeneous nuclei for both borides and austenite during solidification.Thus,the eutectic borides were more dispersed in the modified steel.Moreover,lots of fine‘eutectic cells’were formed in the matrix regions.As a result of the preferential formation of TiB2 during solidification,the amount of the eutectic borides in the steel modified with Ti was significantly decreased.Besides,the continuity of the eutectic borides network was weakened.In a word,the present work provides a promising method to modify the solidification microstructure for high borated stainless steels.展开更多
基金the National Natural Science Foundation of China(Nos.51374002,51574078 and 51774081)the Fundamental Research Funds for the Central Universities(No.N160705001)+1 种基金China Postdoctoral Science Foundation(Nos.2014M560218 and 2016T90228)the Student’s Platform for Innovation and Entrepreneurship Training Program(No.160111)。
文摘To study the effects of rare earth(RE)and Ti on the solidification micros true ture of high borated stainless steels,1.6 wt%B stainless steel doped with RE and2.1 wt%B stainless steel doped with Ti were prepared by ingot casting,respectively.The solidification microstructure of researched steels was characterized in detail.The modification mechanism was clarified based on the heterogeneous nucleation theory and the thermodynamic calculation.The solidification microstructure of 1.6 wt%B and 2.1 wt%B stainless steels was characterized by the continuous and network-like eutectic borides around the matrix grains.It was found that the fine RE compounds could act as the heterogeneous nuclei for both borides and austenite during solidification.Thus,the eutectic borides were more dispersed in the modified steel.Moreover,lots of fine‘eutectic cells’were formed in the matrix regions.As a result of the preferential formation of TiB2 during solidification,the amount of the eutectic borides in the steel modified with Ti was significantly decreased.Besides,the continuity of the eutectic borides network was weakened.In a word,the present work provides a promising method to modify the solidification microstructure for high borated stainless steels.
