Quantitative determination of the generalized stability of Fe-based binary alloys

Our recent study [Acta Mater. 201 (2020) 167-181] proposed a unified generalized stability (GS) criterion to design high-performance metallic materials, but quantitative determination the GS of plasticity deformation remains a big challenge. Here, by combination of molecular dynamics simulations with the classical dislocation thermos-kinetic theory, we reliably calculate the thermo-dynamics driving forces AG, kinetic energy barrier Q, and subsequently predict the GS values of Fe-based binary alloys. Our calculation shows that the GS values of pure alpha-Fe increase from 0 at yield point to 2.7 at uniform elongation stage, and the GS values of Fe-based alloy increased with the increase of alloy content. These results imply that for different systems large GS correspond to the thermodynamically more unstable status that is hard to sustain more dislocation evolution, i.e., low plas-ticity. This quantitative calculation provides a general guideline to use GS theory for further design alloys with excellent mechanical properties.

Automated summary

Our recent study proposed a unified generalized stability (GS) criterion to design high-performance metallic materials, and the quantitative determination of the GS of plasticity deformation remains a challenge. By combining molecular dynamics simulations with classical dislocation thermos-kinetic theory, we calculated the thermo-dynamics driving forces AG, kinetic energy barrier Q, and predicted the GS values of Fe-based binary alloys. The results showed that larger GS values correspond to a thermodynamically more unstable state with low plasticity.