抄録
Rapidly solidifed Al-0.6%Fe and Al-0.8%Fe-0.1%Mg alloys containing metastable Al6Fe and AlmFe were isochronally and isothermally heated at elevated temperatures. X-ray diffraction and optical and transmission electron microscopies were carried out on the phase change of these metastable phases. The metastable phases are directly transformed into stable Al3Fe not through any intermediate compound. The phase change mainly proceeds in the following process; that is, dissolution of the metastable phase in matrix and precipitation of Al3Fe phase at fresh sites of dendrite cell boundaries. The activation energy for the change is evaluated to be 70±10kcal/mol. The rate determining step of the change seems to be diffusion of Fe atoms in Al matrix.
