Effect of manganese content and mechanical activation on the $\mathrm{Ni}$–$\mathrm{Al}$–$\mathrm{Mn}$ combustion

The influence of mechanical activation (MA) and $\mathrm{Mn}$ content on the rate and maximum combustion temperature, sample elongation during combustion, size of composite particles, mixture yield after MA, phase composition, and morphology of synthesis products in the $\mathrm{Ni}$–$\mathrm{Al}$–$\mathrm{Mn}$ system was studied. The mechanical activation of the $\mathrm{Ni}+\mathrm{Al}+\mathrm{Mn}$ mixture expanded the manganese content limit, at which it is possible to realize the combustion of samples without preheating, from $14$ to $49\%$ (wt.). Preliminary MA made it possible to synthesize a compound containing all three initial metals – the $(\mathrm{Ni},\mathrm{Mn})\mathrm{Al}$ phase, which is an ordered solid solution of variable composition based on $\mathrm{Ni}\mathrm{Al}$. In addition, after MA, the burning rate, elongation of product samples and their porosity increased, and the maximum combustion temperature decreased. An increase in the proportion of manganese in the $\mathrm{Ni}+\mathrm{Al}+\mathrm{Mn}$ mixture led to a decrease in the size of composite particles, elongation of product samples, the maximum combustion temperature, and an increase in the yield of the mixture after MA. The dependence of the combustion rate on the proportion of manganese in the activated mixture $\mathrm{Ni}+\mathrm{Al}+\mathrm{Mn}$ has a maximum.