Investigation of binder-jetted gyroid lattice sand molds for thermal dissipation and solidification control

• Gyroid lattice sand molds enable controllable cooling for regulated solidification in sand casting. • Compressive performance is governed by coupled effects of lattice geometry and effective material fraction. • Forced convection increased cooling rates to over 1.0 °C/s in Gyroid lattice molds. • Optimized 20–2.0 mold improved cooling by 35% and reduced grain size by 42% in EV31A castings. Precise control of cooling during sand casting remains challenging, as conventional dense and hollow sand molds provide limited regulation of local cooling rates. This study develops Gyroid lattice sand molds with controllable thermal dissipation, enabling regulation of cooling rates and subsequent control of solidification behavior in EV31A magnesium alloy castings. Using binder jetting, Gyroid lattice molds with different unit cell sizes and mid-surface offsets were fabricated, and their manufacturability, compressive performance, cooling behavior, and solidification response were evaluated under adiabatic, natural, and forced convection conditions. Results show that larger unit cell sizes increase pore scale and reduce effective material fraction, leading to intensified stress concentration and reduced compressive strength, whereas increasing mid-surface offset improves material continuity and redistributes stress, enhancing load-bearing capacity. Cooling performance is strongly correlated with pore size and cavity throat diameter, and the optimized 20–2.0 configuration achieves cooling rates above 1.0 °C/s under forced convection. Solidification experiments further demonstrate a ∼35% increase in cooling rate and a ∼42% reduction in grain size, confirming the effectiveness of Gyroid lattice molds for cooling regulation and microstructural refinement. Gyroid lattice sand molds offer a promising pathway for lightweight, functional, and cooling-controllable mold design in advanced sand casting applications