Microstructure evolution and accelerated magnetocaloric phase formation of LaFe13.1Co0.7Si1.4 alloy by forging deformation at room temperature

Abstract

In order to improve the preparation process and practical process of magnetic refrigerant, a method of accelerating phase formation by cold compression plastic deformation at room temperature is proposed. To determine the significance of this method, the grain structure, phase composition and magneto-thermal effects of LaFe13.1Co0.7Si1.4 alloy were systematically studied. The results show that with the increase of compression ratio, the number of grains per unit volume increases and the grain size tends to be uniform. Compared with the uncompressed sample, the proportion of magnetothermal phase in the pre-compressed samples increases after annealing under the same conditions. When the deformation is 40%, the ratio of 1:13 phase in pre-deformed sample after 1 day annealing is 72 vol%, which is significantly better than that of the undeformed sample. After annealing for 3 days, the Curie temperature (TC) of 40% pre-deformed LaFe13.1Co0.7Si1.4 samples is 330 K, and the magnetic entropy changes to − 4.70 J/kg K and − 5.42 J/kg K under 2 T and 3 T magnetic fields, respectively. The appropriate Curie temperature and value of ∆SM make it an attractive potential candidate for magnetic refrigeration application at room or even high temperature.