Microstructure and Strength of Yttria-Reinforced Aluminum by ARB

The effects of accumulative roll bonding (ARB) on the microstructure and mechanical properties of an AA 1060/Y₂O₃ nanocomposite are investigated. AA 1060 alloy sheets that had been pre-rolled to a thickness of 1 mm were annealed at 430 °C, stacked with Y₂O₃ nanoparticles, and roll-bonded with a 50% thickness reduction per pass up to five passes. FESEM images, tensile testing (ASTM E8), and Vickers hardness measurements were used to characterize the material. With an increasing number of ARB passes, the dispersion of the Y₂O₃ particles within the AA 1060 sheets improved, as indicated by the increasing value of the dispersion index D (from 0.35 at pass 1 to 0.81 at pass 5); the ultimate tensile strength of the nanocomposite sheets increased from 77.5 MPa for the as-annealed sheets to 187 MPa for the sheets after five passes of roll bonding, and the hardness of the sheets reached 57.5 HV after five passes of roll bonding (≈2.4× the hardness of the annealed sheets). Furthermore, the elongation of the nanocomposite sheets decreased sharply after the first pass of roll bonding but then stabilized between 3.5 and 5%. A physics-guided saturation model is fitted to the measured UTS data, and leave-one-out cross-validation is used to assess its limited predictive capability.