Explosion characteristics and suppression analysis of AlSi12 powder used in additive manufacturing

To prevent explosion accidents of AlSi12 powder during additive manufacturing, a 20- L spherical explosion apparatus was used to investigate the explosion characteristics of AlSi12 and the suppression effects of NaHCO₃. Additionally, thermal analysis, chemical composition, and surface morphology analysis of the explosion residues were conducted to clarify the suppression mechanisms. The results indicated that the explosion hazard of AlSi12 powder reached its maximum at a concentration of 750 g/m³, with an explosion pressure of 0.710 MPa and an explosion temperature of 801 °C. The addition of NaHCO₃ at an inerting ratio of 2.6 effectively suppressed explosions across all concentrations of AlSi12 powder. NaHCO₃ showed better inhibitory effects on higher concentrations of AlSi12, with greater suppression of explosion temperature compared to explosion pressure. Furthermore, incorporating NaHCO₃ effectively inhibited the oxidation of AlSi12 dust clouds, increasing the apparent activation energy of AlSi12, thereby reducing the probability of explosion. Combined experimental analyses revealed that NaHCO₃ effectively inhibits AlSi12 powder explosions through mechanisms such as heat absorption, prevention of heat transfer, radical capture, and reactant consumption. The consumed reactants are primarily the Al element in the alloy powder, while the Si element is largely unaffected. These findings provide valuable experimental data and theoretical support for preventing and controlling AlSi12 powder explosions.