Experimental study on flame propagation suppression characteristics of Ti-6Al-4V titanium alloy dust

Abstract

Ti-6Al-4V (TC4) titanium alloy, a widely utilized titanium-based material, exhibits exceptional mechanical properties and corrosion resistance, making it indispensable in aerospace, biomedical, and chemical process applications. However, in fine particulate form, it presents significant combustibility and explosion hazards. To enhance safety protocols and industrial explosion prevention strategies for TC4 titanium alloy dusts, this study investigates the suppression effects of melamine pyrophosphate (MPP), CaCO₃, and TiO₂ on flame propagation characteristics using an improved Hartmann tube apparatus. The explosion suppression mechanisms of these three agents are analyzed through detailed explosion residue examination. The results indicate that as suppressant content increases, flame fronts gradually transform into regular parabolic shapes, while bright luminous regions progressively contract until dust extinction occurs. The presence of suppressants significantly reduces the flame propagation velocity of the mixed dust. With increasing suppressant concentration, the time required for flame propagation velocity to reach its peak increases, while the maximum flame propagation velocity continuously decreases. MPP suppresses TC4 titanium dust explosions through both physical mechanisms (heat transmission, cooling, and hindering oxygen) and chemical mechanisms through capturing free radicals within chemical reaction. In contrast, suppression effects of CaCO₃ and TiO₂ on TC4 titanium alloy dust explosion primarily manifest through physical mechanisms such as cooling, impeding oxygen, and heat transfer.