Establishing strain integrated gas infusion (SIGI) casting process for high performance aluminium‑silicon casting

A356 aluminium alloy is a cornerstone material for automotive and aerospace applications owing to its superior strength-to-weight ratio. However, its conventional as-cast microstructure suffers from coarse dendritic networks and elongated, brittle eutectic silicon needles, which drastically compromise ductility and overall mechanical performance. In this study, we present the strain integrated gas infusion (SIGI) casting process, an advanced single step and robust solidification control casting process designed to overcome these long-standing limitations. Through synergistic tool-induced strain and controlled gas infusion, the SIGI process refines microstructure via rapid strain-assisted bubble nucleation, enhanced dendrite fragmentation, and uniform globular grain formation, while breaking silicon needles into fine (refinement by ∼90%) dispersions and forming refined eutectic Mg 2 Si particles. As a result, the alloy exhibits remarkable property enhancement, with tensile strength increased by 155% and ductility improved by 156% with reduction in porosity by ∼78.6% relative to the as-cast baseline. This research demonstrates that the SIGI process tailors the microstructure at multiple length scales and unlocks the full performance potential of A356, positioning it as a next-generation solution for aluminium‑silicon cast applications.