Effects of milling intensity on amorphisation of Al–Fe mixed powders by mechanical alloying

Abstract

The effects of milling intensity on the amorphisation of Al–Fe powder mixtures containing 10, 15, 20, and 25 at.-% Fe, during mechanical alloying by a high energy planetary ball mill, have been investigated. Two levels of milling intensity, 80g and 150g (where g is acceleration due to gravity), were adopted. Two different pathways of amorphisation reaction were found; Al–Fe solid solution → amorphous phase; and Al–Fe solid solution → formation of Al₅Fe₂ phase → amorphous phase. The former reaction was observed in Al–10, –15, –20, and –25 at.-%Fe compositions at the lower milling intensity and in Al–10 at.-%Fe at the higher milling intensity. The latter reaction was observed in Al–15, –20, and –25 at.-%Fe compositions at the higher milling intensity. The two pathways of amorphisation reaction are explained mainly by a kinetics approach.