• Submicron TiB2 particles significantly refine the grain structure of Al-Cu (ZL205A) alloy, transforming coarse grains into fine equiaxed grains.
• Adding 3wt.% TiB2 improves fluidity by 20% and reduces hot tearing susceptibility by 29%, enhancing castability.
• Optimal mechanical properties (hardness and strength) are achieved with 1wt.% TiB2 addition, balancing reinforcement and ductility.
• A TiB2 content of 1wt.% is recommended for optimizing both casting performance and mechanical properties in ZL205A alloy.