Deformation and fracture of single crystals of VKNA-type alloys at 1100–1250°C

A comparative study of the structure and mechanical properties of single-crystal samples 〈001〉 of VKNA-1V and VKNA-4U alloys (cast and after heat treatment) has been performed using tensile tests in a temperature range of 1100–1250°C. In the case of the VKNA-4U alloy, samples of different crystallographic orientations have also been tested. At 1100°C, recrystallization was observed near the zone of fracture. The basic mechanism of relaxation at 1200–1250°C was found to be dynamic recovery. At 1250°C, the strength properties of the VKNA-4U alloy are higher than those of the VKNA-1V alloy.