Microstructural aspects of gasless combustion of mechanically activated mixtures. I. High-speed microvideorecording of the Ni-Al composition

International audience; Gasless combustion of a mechanically activated Ni-Al mixture is experimentally studied; the process is compared with the characteristics of combustion of a nonactivated Ni-Al mixture. Mechanical activation of the Ni-Al mixture is shown to form layered conglomerates consisting of numerous layers of the initial components. As a result, the structure of the medium becomes very similar to a cellular structure, which forms the basis for advanced microheterogeneous models of gasless combustion. A relation between the local (microscopic) and global (macroscopic) parameters of gasless combustion is found. Modification of the microstructure of the initial medium by means of mechanical activation allows obtaining products whose microstructure differs significantly from the microstructure of products obtained from nonactivated mixtures.