Resumo
The combustion velocities of two fractions of mechanically activated Ni + Al mixtures are compared in this paper. The combustion of pressed samples and samples of bulk density is studied. The main aim of the study is to experimentally verify the main conclusions of the microheterogeneous model of gas-free combustion at the macrolevel using an activated Ni + Al mixture as an example. The relative elongation, the combustion velocity of the samples, the macrostructure, and phase composition of the synthesis products are studied. The combustion velocity is maintained with a change in the density of the samples and slightly increases with a decrease in the size of the composite particles. It is established that pressed samples during combustion elongate more strongly than samples from bulk density. Samples consisting of large particles elongate more strongly during combustion than samples consisting of smaller particles. The phase composition of combustion products depends on the fraction of composite particles and sample density. An explanation of the regularities observed in this study is proposed.