Hydrogen-induced amorphization in CeAl alloys

Abstract

Hydrogen-induced amorphization (HIA), i.e., formation of an amorphous phase by hydrogen absorption of intermetallic compounds, has been investigated in the last decade as a novel preparation method of amorphous alloys without liquid quenching. HIA is reported in many compounds, which are almost C15 Laves RM{sub 2} compounds (R = rare earth metal, M = ferromagnetic metal of Fe, Co, Ni). This leads to a question whether HIA is a popular phenomenon limited just to C15 Laves RM{sub 2} compounds. Recently, the present authors have shown that HIA occurs in many R-Al compounds (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er as well as Y). Furthermore, the behavior of amorphization from crystalline state and the behavior of crystallization from the corresponding amorphous state in R-Al alloys are fairly different from those in Laves RM{sub 2} compounds. For a more detail study as presented in this paper, Ce-Al alloys have been chosen because they are taken as representative. In the Ce-Al alloys, there are five intermetallic compounds. As CeAl{sub 3} and Ce{sub 3}Al{sub 11} seldom absorb hydrogen, this study will focus on Ce{sub 3}Al, CeAl and CeAl{sub 2}.