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

Abstract The AB-type Ti 1.1- x RE x Fe 0.8 Mn 0.2 (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 Ti 1.1 Fe 0.8 Mn 0.2 (TFM for short) alloy includes the base phase of TiFe phase and the second phases of TiFe 2 phase and TiO phase. Backscatter electron (BES) images show that there is Ti segregation phase besides TiFe phase and TiFe 2 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 Ti 1.1- x RE x Fe 0.8 Mn 0.2 (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 Pr 0.01 , Sm 0.01 and Nd 0.01 alloys, respectively. And it also is able to weaken the stability of the hydrides, while causes variable degrees of the hydrogenation capacity decrease.