Rapidly solidified (RS) Al-TM (TM = transition metal) alloys are perspective
materials from scientific, as well as technological point of view. Generally, they are produced
by the melt atomization or by the melt spinning. Subsequent compaction is commonly
performed by the hot extrusion. Since transition metals, such as Cr, Fe, Ni, Zr, Ti, Mn and
others, have low diffusion coefficients in solid aluminium (lower by several orders of
magnitude than those of common alloying elements like Cu, Si, Mg, Zn etc.) the RS Al-TM
alloys are characterized by a high thermal stability. In this paper, several RS Al-TM
(TM = Cr, Fe, Ti, Mn, Ni) alloys prepared by the melt spinning and melt atomization are
compared to commercially available 2xxx, 6xxx and 7xxx wrought alloys. The main
structural features of both RS and wrought alloys are described. The RS alloys are
characterized by the presence of micro and nano-scale crystalline and/or quasi-crystalline
phases and supersaturated solid solutions. The elevated-temperature behaviour is compared
for both groups of materials. The thermal stability of the investigated materials is determined
by room temperature hardness measurements after various annealing regimes and a high
thermal stability of the RS alloys is demonstrated. The microstructural changes and phase
transformations occurring in the investigated materials upon heating are described. In the
Al-TM alloys, very slow decomposition of the supersaturated solid solutions, precipitation
and decomposition of the metastable quasi-crystalline phases occur.
MICROSTRUCTURE AND THERMAL STABILITY OF Al-Fe-X ALLOYS
