Assessing microstructures and mechanical resistances of as-atomized and as-extruded samples of Al-1wt%Fe-1wt%Ni alloy

Current applications of Al-Fe-Ni alloys include Alnico permanent magnets, industrial furnaces, and cladding of nuclear fuel plates. In spite of industrial interest, limited knowledge regarding to interrelations between microstructure and mechanical resistance can be noted to date. Thus, the aim of the present contribution is, firstly, to analyze the microstructure features of alpha-Al phase (size and morphology) during atomization of the ternary Al-1wt%Fe-1wt%Ni alloy, including determination of cooling rates and hardness of the obtained powders. Secondly, the nature, size and distribution of intermetallic compounds (IMC), strength and ductility of hot consolidated bulks by extrusion from two different ranges of Al-Fe-Ni powder size (powder size between 75 and 106 mu m and powder size up 106 mu m and less 180 mu m) are examined. The sequence of processes includes nitrogen gas atomization followed by compaction and hot extrusion consolidation at both 350 degrees C and 400 degrees C. The procedures to characterize the samples involve X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), Vickers hardness and mechanical tensile tests. Al-rich cells prevailed for either smaller or larger Al-1wt%Fe-1wt%Ni atomized powders with formation of IMCs not only in the cell walls but also precipitated within the alpha-Al matrix. Strength and ductility of as-extruded samples are found to be consistent with their microstructures. (C) 2016 Elsevier B.V. All rights reserved. (AU)