Metallurgical characterization of thermomechanically processed U-0.75 wt.% Ti

Abstract

The objective of this study was to develop higher strength U-0.75 wt.% Ti by thermomechanical procedures. The approach was to replace the conventional solution treated, quenched, and aged (STA) process for U-0.75 wt.% Ti with warm rolling and warm or cold swaging. The effect of working on structure, hardness, tensile properties, compressive strength, and fracture toughness was determined. Deformation strengthening of previously hot-extruded and slow-cooled U-0.75 wt.% Ti was found to significantly increase the hardness, the tensile and compressive yield strengths, the ultimate tensile strength, and the reduction in area. There was no appreciable change in fracture toughness. The combinations of strength, ductility, and toughness obtained by deformation strengthening of this as-extruded material were generally inferior to those characteristic of STA processing. U-0.75 wt.% Ti, which was solution treated, water quenched, and warm rolled to a large reduction and then cold swaged, achieved the highest values in hardness, tensile and compressive yield strength, and ultimate tensile strength. Fracture toughness values were comparable to the conventionally processed alloy and reduction in area values were significantly greater. Deformation strengthening of solution treated and quenched material resulted in substantially better combinations of strength, ductility, and toughness than those characteristic of STA processing.