Nouvelle approche pour améliorer les performances du froid élastocalorique de l’alliage Fe_85.4Ni_14.6(à %) par polycristallisation :une recherche de type dynamique moléculaire.

This work introduces a polycrystallization-based approach to improve the elastocaloric refrigeration performance of the Fe_85.4Ni_14.6 (at%) alloy, as revealed by molecular dynamics simulations. The simulation results demonstrate that the stress–strain response of the polycrystalline alloy (PCA) features a single peak, suggesting that PCA circumvents the superelastic and yield stages without pre-stretching. Moreover, the peak’s shift to lower strain further induces the elastocaloric effect (eCE) under reduced deformation. The adiabatic temperature change of PCA is 214 K, significantly higher than the 50 K observed in single-crystal alloy (SCA), demonstrating a clear improvement in refrigeration performance. Furthermore, energy dissipation and phase transition analyses reveal that the thermal motion of atoms under varying temperatures drives the phase transitions. This work presents a novel approach to enhancing the elastocaloric refrigeration performance of Fe_85.4Ni_14.6 (at%) alloy and provides a theoretical basis for its experimental preparation.