Shock adiabat features,phase transition macrokinetics,and spall fracture of iron in different phase states

Abstract

Results are presented of systematic experimental investigations of shock adiabat and evolution of multiwave configurations for a number of steels in the range up to 100GPa; of stress relaxation kinetics in the front of the elastic and phase precursor from different initial states: uσ_x = 15, 25, 49, and 59GPa; and of data on spa11 fracture of iron in α —, ε —, γ —, and liquid phases under conditions of uniaxial deformation as well as under volumetric omnidirectional tension. Changes in material microstructure and microhardness of samples subjected to shock wave loads of 15, 25, 200, and 1000 GPa are analyzed.

Investigations of steels with the initial state in α and γ phases of iron and with different original heat treatment show that, in stress waves of low intensity (σ_x? 10–25 GPa), as well as under quasi-static tension-compression tests and impact tests, differences in their behavior and properties are clearly displayed. As the amplitude of longitudinal stresses increases up to 200–250 GPa, differences in their compressibility and in the character of spal1 fracture begin to smooth down.