Microstructural Evolution and Magnetocaloric Properties of Cold Plastically Deformed LaFe10.9Co0.7Si1.4 Compound

To optimize the formation of the magnetocaloric 1:13 phase in La(Fe,Si)(13)-based compounds, a method to improve the preparation process and promote the practical application of magnetic refrigeration is proposed. The LaFe10.9Co0.7Si1.4 and LaFe13.1Co0.7Si1.4 samples were plastically deformed to different degrees by cold compression at room temperature. Subsequently, grain structure, phase composition, and magnetocaloric effects were systematically investigated. The results demonstrated that the pre-deformation process can effectively increase the number of grains per unit volume and homogenize the grain size. Using the same annealing temperature and time, the 1:13 phase in the pre-compressed samples was much higher than that in the uncompressed samples, whereas the compression deformation did not cause an uneven elemental distribution. Compared to LaFe13.1Co0.7Si1.4, the LaFe10.9Co0.7Si1.4 compound obtained by the same preparation process has a higher magnetocaloric phase ratio. After short annealing for 3 days, the Curie temperature (T-C) of 40% pre-deformed LaFe10.9Co0.7Si1.4 sample reaches 303 K, and the magnetic entropy change of 5.30 and 10.55 J/kg K under 2 and 5 T magnetic fields is observed. The good magnetic refrigeration-related performance makes the 40% pre-deformed LaFe10.9Co0.7Si1.4 alloy a potential candidate for room temperature magnetic refrigeration.

Automated summary

In order to optimize the formation of the magnetocaloric 1:13 phase in La(Fe,Si)(13)-based compounds, a method to improve the preparation process and promote the practical application of magnetic refrigeration is proposed. Plastic deformation of LaFe10.9Co0.7Si1.4 and LaFe13.1Co0.7Si1.4 samples through cold compression at room temperature resulted in increasing the number of grains per unit volume and homogenizing the grain size. The pre-compressed samples showed a much higher 1:13 phase compared to the uncompressed samples without an uneven elemental distribution. The LaFe10.9Co0.7Si1.4 compound obtained through the same preparation process exhibited a higher magnetocaloric phase ratio compared to LaFe13.1Co0.7Si1.4.