Effects of TiB2 on microstructure, mechanical properties, and fluidity of AlSi10MnMg alloy fabricated by high-pressure die casting

• Addition of 0.018wt.% TiB2 significantly reduces externally solidified crystals (ESCs) and porosity, improving filling distance from 1,700 mm to 1,833 mm in HPDC AlSi10MnMg alloy. • TiB2 promotes migration of ESCs toward the melt center where temperature and flow velocity are higher, enhancing fluidity and mechanical properties. • At a filling distance of 1,300 mm, 0.018wt.% TiB2 notably increases ultimate tensile strength, yield strength, and elongation. • Increasing TiB2 to 0.036wt.% improves short-distance mechanical properties but degrades performance beyond 1,000 mm due to increased ESCs and reduced filling distance.