Structure and hydrogenation performances of as-cast Ti1.1-xRExFe0.8Mn0.2 (RE = Pr, Sm and Nd; x = 0, 0.01) alloys

The AB-type Ti1.1-xRExFe0.8Mn0.2 (RE = Pr, Sm and Nd; x = 0, 0.01) alloys in cast are fabricated. The relationships of phase composition, surface morphology and crystal structure to the hydrogenation performances of the alloys are studied. X-ray diffraction (XRD) results show that the as-cast Ti1.1Fe0.8Mn0.2 (TFM for short) alloy includes the base phase of TiFe phase and the second phases of TiFe2 phase and TiO phase. Backscatter electron (BES) images show that there is Ti segregation phase besides TiFe phase and TiFe2 phase in the TFM alloy. Substituting Ti with RE partly causes Ti phase to increase and RE phases to generate. The lowest activation temperature decreases from 573 K for the TiFe alloy to 423 K for the Ti1.1-xRExFe0.8Mn0.2 (RE = Pr, Sm and Nd; x = 0, 0.01) alloys. Substituting Ti with RE partly makes the incubation time reduce from 5900 s for the TFM alloy to 3850, 3900 and 4050 s for the Pr0.01, Sm0.01 and Nd0.01 alloys, respectively. And it also is able to weaken the stability of the hydrides, while causes variable degrees of the hydrogenation capacity decrease.