Effect of Fe–Co–Cr content and mechanical activation on combustion in a Ni–Al–(Fe–Co–Cr) system

The influence of mechanical activation and amount of Fe + Co + Cr binder on the combustion rate and maximum temperature, sample elongation during combustion, composite particle size and mixture yield after activation, phase composition and morphology of synthesis products in the Ni–Al–(Fe–Co–Cr) system was studied. Mechanical activation of the Ni + Al + $x$(Fe + Co + Cr) mixture allowed the samples to burn at room temperature with a Fe + Co + Cr binder content of up to 40%. Activation of the mixtures increased the combustion rate and temperature, sample elongation and porosity, and decreased their strength. An increase in the Fe + Co + Cr binder content in the activated Ni + Al + $x$(Fe + Co + Cr) mixture led to an increase in the mixture yield after mechanical activation, a decrease in the composite particle size and an elongation of the synthesis product samples. The dependence of the combustion rate of activated mixtures on the content of the Fe + Co + Cr binder is non-monotonic, and has a maximum at a binder content of 10%. High-entropy alloys – solid solutions based on intermetallic compounds NiAl and Ni$_3$Al – were synthesized by the SHS method.