Gas-free combustion of $\mathrm{Ti}$–$\mathrm{C}$–$\mathrm{Al}$ reaction mixtures in a thermal explosion

Phase composition of thermal explosion products in compacts made of $\mathrm{Ti}$–$\mathrm{C}$–$\mathrm{Al}$ powder mixtures with an equiatomic ratio of titanium and carbon (soot) and with an aluminum content of $10\div40\%$ (wt.) is studied. The compacts are heated at a rate of $40\pm 5^{\circ}$C /min in an argon atmosphere. Self-ignition temperature of all compositions was close to the melting point of aluminum ($660^{\circ}$C). Peak temperatures and the maximum rate at which temperature elevation becomes higher as the aluminum powder content in the mixtures increases. Synthesis products contain titanium carbide and $\mathrm{Al}_2\mathrm{Ti}$ titanium trialuminide, whose ratio depends on the aluminum content in the mixture. Pretreatment of reaction mixtures in a planetary mill flattens aluminum particles, thereby preventing the formation of a melt. The spreading of a melt over the titanium surface with subsequent reaction diffusion and the formation of $\mathrm{Al}_2\mathrm{Ti}$ increases the temperature in compacts made of nonactivated mixtures.