Nanometer dual-phase dispersion strengthened aluminum resistant to ultrahigh-temperature softening

Conventional pure aluminum is prone to recrystallization softening, making it unsuitable for high-temperature applications. To address the issue, this study proposes an in-situ dual-phase dispersion strengthening strategy incorporating AlF 3 and Al 2 O 3 nanoparticles. Using powder metallurgy and hot extrusion processes, an aluminum alloy resistant to ultra-high temperature softening above 550 °C was successfully fabricated. Results show that the material can maintain high hardness even after annealing at 550 °C, with only an 11.5 % hardness reduction compared to room-temperature. The sample with 2 wt% PTFE addition exhibits a tensile strength of 168 MPa, 28 % improvement over pure aluminum, while maintaining excellent ductility with an elongation of 24.3 %. The strength improvement primarily stems from strong dislocation pinning by AlF 3 and Al 2 O 3 nanoparticles and effective suppression of grain boundary migration by the cubic AlF 3 particles. This study expands the conventional understanding of dispersion-strengthened aluminum and opens new pathways for developing super heat-resistant aluminum alloys.