Peculiarities of structural transformation in plastic materials under abrupt changes in loading conditions

In the work, a new type of mechanical tests is used in which the system under study is a mechanical system comprising three simultaneously loaded parallel elements: a test specimen and two brittle auxiliary specimens whose fracture causes an abrupt change in the strain rate of the test specimen. In the test, part of the kinetic energy released during the fracture of the auxiliary specimens is dissipated in the test specimen resulting in considerable structural changes and increased plasticity. Transmission electron microscopy analysis of the structure of deformed armco-iron and D16 alloy shows that the increase in plasticity during dynamic nonequilibrium processes is due to the formation of dissipative structures, namely localized bands. Quantitative statistical analysis of the band parameters reveals the absence of scale invariance typical of relaxation structures (cells, recrystallized grains).