Dynamic shear and spall strengths of preliminarily quasi-statically extruded fine-grained uranium and U-0.3% Mo alloy

It is shown that substantial changes in the average grain size (by two orders of magnitude) and a twofold increase in the quasi-static yield stress and strength for uranium and 1.3-fold increase for the U-0.3% Mo alloy did not lead to a change in their shear strength upon a shock-wave loading. There is no correlation between the change in the shear and spall strength and the decrease in the average grain size. A tendency toward a regular increase (other conditions, i.e., amplitudes and the durations of the loading pulse, being equal) in the spall strength of materials in the row “extruded U, extruded U-0.3% Mo alloy, cast U-1.5% Mo alloy” was noted. The increase in the spall strength is connected with alloying and the real content of molybdenum in the alloy rather than with the effect of extrusion.