| 摘 要： | In the present work we reported the phase formation, microstructure, magnetocaloric effect and hydrogenation behavior of La-rich La1.7Fe11.6Si1.4alloy. In this off-stoichiometric La(Fe,Si)13alloy, the Na Zn13-type La(Fe,Si)13matrix phase shows faceted grains, with the Cr5B3-type La5Si3 used as the secondary phase distributed intergranularly. Such a peculiar morphology quickly forms upon one day annealing. In La1.7Fe11.6Si1.4alloy, we have observed a significant field dependence of magnetostructural transition temperature(～ 6.3 K/T), resulting in a large and table-like entropy change(△S～ 18 J/kg·K in 2 T) over a broad temperature range(～ 10 K). Upon hydrogenation, the maximum value of △S keeps almost unchanged, while the Curie temperature increases up to 350 K. These results indicate that the investigated offstoichiometric La(Fe,Si)13alloy is a promising magnetic material for magnetic refrigerators.
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