Al2O3 network and nanoprecipitation for synergistic strengthening of Al-Cu-O composites

Al powder is prone to oxidation, which can introduce impurities in powder metallurgy. In this study, Al₂O₃ nanonetworks were obtained by destroying the oxide layer through Paulse Activated Sintering (PAS). The network and the nano-precipitation enhance the mechanical properties of Al-Cu-O composites. TEM analysis revealed the formation of CuAl₂ and an Al₂O₃ network at the grain boundaries. The current facilitated the modulation of the intermetallic compound size and the fragmentation of the oxide layer. The current-induced discharge at the particle interfaces generated localized heating. Higher temperature effectively disrupts the oxide layer. The Al₂O₃ network improved the fracture toughness of the Al-Cu-O composites by passivating crack propagation. Simultaneously, the current reduced the nucleation barrier for precipitation by promoting directional atomic migration. Uniformly dispersed nano-precipitates are conducive to the improvement of strength. This study provides new insights into oxidation-related challenges in Al powder.