Enhancing high-temperature performance of AlCu alloys via nanoceramic particle-induced grain boundary stabilization and precipitate manipulation

Abstract

AlCu alloys are widely employed in the automotive and aerospace industries owing to their exceptional mechanical properties. However, their performance degradation at elevated temperatures restricts broader applications. Departing from conventional alloying approaches, this study introduces a novel strategy to enhance the high-temperature mechanical properties of AlCu alloys through grain boundary stabilization and precipitation manipulation via the incorporation of trace meticulously designed TiC–TiB₂ nanoceramic particles. These particles inhibit element segregation and facilitate the transformation of intergranular second phases into a finer, reticular structure, thereby stabilizing the grain boundaries. Additionally, the nanoparticles increase dislocation density, serving as preferential nucleation sites for precipitation. The larger lattice distortion around the precipitates also triggered the formation of stacking faults. Consequently, a more refined and uniform distribution of nano-precipitates enhances interactions with dislocations, imparting greater deformation resistance., The ultimate strength (310 MPa) and fracture strain (10.2 %) of 0.15 wt% particle reinforced AlCu alloy achieves a synergistic improvement in both high-temperature strength and toughness, which are improved by 28 % and 64 % at 473 K compared with the matrix alloy. This work offers valuable insights for developing high-performance, heat-resistant AlCu alloys, paving the way for advanced industrial applications.