The effect of the metal binder content and mechanical activation on combustion in the (Ti + 2B) + (Ti + C) + x(Fe + Co + Cr + Ni + Al) system

The paper investigates the effect of the content of the Fe + Co + Cr + Ni + Al metal binder and mechanical activation (MA) on the combustion rate, elongation of samples during synthesis, mixture yield and size of composite particles after MA, morphology and phase composition of combustion products and activated mixtures in the system (Ti + 2B) + (Ti + C) + x(Fe + Co + Cr + Ni + Al. In the process of MA mixtures, a multicomponent high–entropy alloy is formed – a solid solution based on γ-Fe with a HCC lattice (MHEA). A composite material consisting of ceramics and a high-entropy alloy was obtained by the method of self-propagating high-temperature synthesis (SHS). MA increases the maximum content of the metallic binder in the mixture, at which SHS is carried out at room temperature, from 60 to 80%. After MA, the elongation of the product samples and the combustion rate (in the case of a metal binder presence) of mixtures (Ti + 2B) + (Ti + C) + x(Fe + Co + Cr + Ni + Al) increases. For a mixture (Ti + 2B) + (Ti + C) without a binder, the combustion rate decreases after MA. With an increase in the content of the metal binder Fe + Co + Cr + Ni + Al in mixtures (Ti + 2B) + (Ti + C), the size of composite particles increases, the combustion rate, the yield of the activated mixture and the elongation of the samples of the reaction products of MA mixtures decreases. For the initial mixtures, the dependence of the elongation of the combustion product samples on the content of the binder is nonmonotonic, has a maximum.