Crystallization behavior of spray-formed and melt-spun Al89La6Ni5 hybrid composites with amorphous and nanostructured phases

Abstract The crystallization behavior of spray-formed and melt-spun Al 89 La 6 Ni 5 alloys was studied. Spray forming process could produce a bulk scale Al 89 La 6 Ni 5 hybrid composite consisting of amorphous and nanostructured phases directly without the need of an amorphous precursor. The fraction of amorphous phase in the spray-formed composite was determined to be 36% by DSC, which came mostly from supercooled liquid droplets upon spray forming. Amorphous phase partially devitrified to nano-scale fcc-Al secondary crystals during deposition. Two significant primary crystals observed in the spray-formed bulk hybrid composite are Al 3 Ni and Al 11 La 3 (Ni), but their size is reduced to about 1 μm. Contrary to the microstructure of spray-formed deposit, the heat-treated and fully devitrified melt-spun ribbon hybrid composite consists of nano-scale fcc-Al, Al 3 Ni, Al 11 La 3 as well as some metastable Al 6 Ni and Al 4 LaNi phases with sizes of about 200 nm. Deformation twins were found in the Al 11 La 3 (Ni) crystals in spray-formed deposit, but not in the fully devitrified ribbon. Finally, the microstructure structure evolution of spray-formed deposit and heat-treated ribbon are studied and proposed.