Precipitation process of vanadium carbide in M23C6 by atomic-scale configuration analysis

Abstract

The effect of vanadium (V) on the nucleation of M23C6 and vanadium carbide (VC) precipitation in Fe–Cr–V alloy was studied by field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy and thermodynamic calculations. The results revealed that the lattice constant of M23C6 decreased when V atoms diffused into M23C6, which resulted in a reduction in the strain energy and increase in the driving force for the nucleation of M23C6. The V-rich zone was also formed in M23C6 as the V content increased, thereby resulting in the precipitation of a new VC particle adjacent to M23C6 as well as a new orientation relationship (OR), specifically $$ (1\bar{1}1)_{\text{VC}} //(2\bar{4}2)_{{{\text{M}}_{23} {\text{C}}_{6} }} $$ and $$ [011]_{\text{VC}} //[111]_{{{\text{M}}_{ 2 3} {\text{C}}_{ 6} }} $$ . Based on the OR, the formation process of VC in M23C6 was discussed by atomic-scale structure analysis.