Powder consolidation of Al-10Â wt% Fe alloy by High-Pressure Torsion

Mixtures of high-purity elemental powders of Al with an Fe content of 10 wt% were consolidated at room temperature by means of High-Pressure Torsion (HPT) and subsequently deformed to high levels of strain. Relative density of the consolidated disks was >99% even at low strains. The microstructure observation by transmission electron microscopy revealed that the alloy consisted of an ultrafine grained Al matrix with an average grain size of 145 nm. Supersaturation of Fe was estimated in the matrix to a maximum of ∼1 wt% Fe by X-ray diffraction. The dispersion of secondary Fe-rich particles was quantified by scanning electron microscopy and image processing techniques. Hardness and tensile strength were improved significantly with straining by HPT, in direct correlation with grain refinement and potentiated by dissolution of Fe particles in the matrix. Excellent compromise of strength and ductility was achieved at intermediate levels of imposed strain.