Phase composition and transformation behavior of readily solidified Al-Ni-Fe alloys in α-Al-decagonal phase region

The structure and transformation behavior of two series of alloys located in the ternary concentration triangle in the Al-Ni-Fe system between aluminum and decagonal phases with two different periodicities have been investigated. The rapidly solidified alloys have the following compositions: Al100−x(T-2)x (x = 10-100) and Al100−x(T-8)x (x = 30-100) in which T-2 and T-8 refer to the Al71.6Ni23.7Fe4.7 and Al75Ni10Fe15 single decagonal phase alloys, respectively. No evidence indicating the formation of coexistent decagonal and aluminum phases was found in low and medium decagonal-component contents (Al-rich side), either in the as quenched or in the annealed state. As Fe and Ni increase, the decagonal phase forms. The increase in hardness with the transition-metal content of the decagonal component in different alloys is attributed to solution hardening, formation of the dispersed fcc-Al in amorphous matrix, and the dispersion of hard intermetallics including the decagonal phase.