Influence of carbide precipitation behavior on mechanical properties of Fe-Mo-Cr-C alloy steels during spheroidal annealing
The difference of carbides in Fe-Mo-Cr-C alloy steels in terms of number,size and composition by different spheroidal annealing holding time was systematically investigated using scanning electron microscopy(SEM).The results show that the higher hardness of the specimens with longer annealing time is due to the dissolution of more eutectic carbides during austenitization and the precipitation of a greater number of secondary carbides of the M6C(Fe3Mo3C)type with smaller sizes.The first-principle calculations show that Fe3Mo3C has the best overall performance,which is conducive to the improvement of the overall mechanical properties of the steel among the carbides of Fe-Mo-Cr-C alloy steels in the annealed condition.Different high and low energy levels and differences in orbital hybridization of Fe-d,Mo-d,C-d and C-p are responsible for the superiority of Fe3Mo3C over Fe2Mo4C,which is also a M6C-type carbide,both in terms of structural stability and mechanical properties.The effect of carbides on mechanical properties of steel in spheroidal annealing was studied,which can provide a theoretical basis for other mold steel materials in the heat treatment process technology.
spheroidal annealingcarbidefirst-principleelastic constantdensity of states
万方数据
维普
