Structure and Phase State of Zr-1% Nb and Zr-2.5% Nb Alloys Loaded by Spherically Converging Shock Waves

Four balls made of zirconium-niobium alloys are loaded by spherically converging shock waves of various intensities and then studied from layer to layer by X-ray diffraction, optical metallography, transmission electron microscopy, and microhardness measurements. The phase and structural states of the balls are found to depend on the loading conditions and the depth of layer location in a ball. The omega phase is retained in the near-surface layers of the balls only after low-intensity loading, and its content increases with the niobium content in an alloy. The high-rate plastic deformation of the balls, which have a fine-grained structure in the initial state, during loading under our experimental conditions is shown to occur via slip and the formation of adiabatic shear bands.