Effect of Heat-treatment on the Magnetocaloric Properties of Gd_0.6Dy_0.4Co₂ and Gd_0.6Dy_0.4Co_1.9Al_0.1

Alloys Gd_0.6Dy_0.4Co₂ and Gd_0.6Dy_0.4Co_1.9Al_0.1 were prepared by a vacuum arc melting furnace.After heat-treated at 900℃ for 4 days and 7 days, the casting and heat-treated alloys were checked for phases, Curie temperatures, adiabatic temperatures changes and magnetic entropy change.The results reveal that the crystal structure of the alloy becomes to sole GdCo2 structure.Heat-treatment makes the maximum adiabatic temperature of the alloy increase.Compared with casting alloy, the magnetic entropy change of heat-treated alloy increases by 53.2% and 33.1% respectively, and Curie temperature of the alloy decreases slightly.This work shows that the magnetocaloric properties of Gd_0.6Dy_0.4Co₂ and Gd_0.6Dy_0.4Co_1.9Al_0.1 can be effectively improved by heat-treatment.