Al₁₃Fe₄-Al Composites with Nanocrystalline Matrix Manufactured by Hot-Pressing of Milled Powders

The paper describes composites with the matrix containing a nanocrystalline intermetallic Al₁₃Fe₄ phase and microcrystalline aluminium. Mechanically alloyed Al₈₀Fe₂₀ powder, containing a metastable nanocrystalline Al₅Fe₂ phase, was mixed with 20, 30, and 40 vol.% of Al powder and consolidated at 750 °C under the pressure of 7.7 GPa. During the consolidation, the metastable Al₅Fe₂ phase transformed into a nanocrystalline Al₁₃Fe₄ phase. In the bulk samples, Al₁₃Fe₄ areas were wrapped around by networking Al regions. The hardness of the Al₁₃Fe₄-Al composites was in the range of 4.52-5.50 GPa. The compressive strength of the Al₁₃Fe₄-30%Al and Al₁₃Fe₄-40%Al composites was 805 and 812 MPa, respectively, and it was considerably higher than that of the Al₁₃Fe₄-20%Al composite (538 MPa), which failed in the elastic region. The Al₁₃Fe₄-30%Al and Al₁₃Fe₄-40%Al composites, in contrast, showed some plasticity: namely, 1.5% and 9.1%, respectively. The density of the produced composites is in the range of 3.27-3.48 g/cm³ and decreases with the increase in the Al content.