Hercynite pinning delivers enhanced creep resistance in Fe₂O₃–reinforced Al6061: experiments and Arrhenius modeling

Abstract Creep degrades lightweight Al alloys as grains coarsen and reinforcing particles coarsen at high temperature. Adding Fe₂O₃ to AA6061 promotes spinel-type (hercynite-like) reaction products et al./Fe₂O₃ interfaces, which Zener-pins grain boundaries and slows coarsening. Uniaxial creep tests at 473–773 K and 49.1–147.2 MPa cut strain by up to 40% at 673 K and 98.1 MPa versus AA6061, with gains increasing as reinforcement fraction rises and dispersion improves. A unified Arrhenius–Norton law fits the data with R 2 ≈ 0.98 and shows an apparent threshold-stress term consistent with boundary pinning. Microstructural analysis confirms Fe₂O₃ particle dispersion (mean radius, area fraction, and pin density) and shells, uniform dispersion at 2 wt%, and clustering above 4wt%. Indirect EDS evidence suggests Fe–O–Al enrichment consistent with spinel-type interfacial layers, although definitive FeAl₂O₄ identification would require XRD or TEM/SAED. These results demonstrate a scalable, thermally stable route to creep-resistant Al composites for aerospace and automotive use. Graphical Abstract