High thermal stability and mechanical properties of nanosized-Fe-reinforced aluminum matrix composites via deformation-driven metallurgy

Fine-grained aluminum, characterized by high performance and lightweight, is highly susceptible to grain coarsening leading to instability at elevated temperatures. The introduction of the Fe element has shown extraordinary potential to enhance thermal stability, marked by its low solubility and diffusion rate within the Al matrix. In light of this, Fe nanoparticles were exploited to reinforce fine-grained aluminum via deformation-driven metallurgy based on the principle of severe plastic deformation. The inherent mechanisms of dynamic recovery and recrystallization associated with thermo-mechanical properties facilitated the consolidation of ultrafine-grained Al–Fe nanocomposites, resulting in homogeneous dispersion both intragranularly and intergranularly of the reinforcements with an average particle size of 200.2 ± 4.6 nm. These dispersed Al–Fe nanophases with stable structures refined grains and pinned grain boundaries to hinder migration, which significantly enhanced the thermal stability of the composites. The average grain size remained substantially constant after thermal exposure at 300 °C for 100 h, with variability maintained within a 0.20 μm threshold. The mechanical properties remained substantially unchanged, exhibiting an ultimate tensile strength of 480 ± 9 MPa and elongation of 14.8 ± 0.4 %.