First-Principles Study on H Traps at the Interface Between Carbides and α-Fe with Alloy Elements

The trapping behavior of hydrogen atoms at the interfaces between different precipitated carbides (TiC, VC and NbC) and ferrite matrix under alloying elements (Mn, Cr, Mo, Cu, Ni and Si) are studied by first-principles method. The trapping ability of different interface traps are quantitatively compared by analyzing the segregation energies of hydrogen atoms. The trapping ability of mismatched dislocation cores and their intersections is stronger than that of coherent interfaces. The orders of H trapping ability of the carbides in different interface traps are discussed. It is found that the addition of alloy elements leads to an increasement in the segregation energy relative to their corresponding sites in the clean interface, except for Cu addition in VC/Fe and TiC/Fe and Ni in VC/Fe Fe-on-C configurations.