Thermally stimulated acoustic splitting of an elastic wave in polycrystalline niobium subjected to electron-beam remelting

The effect of temperature on the Young’s modulus of electron-beam-remelted polycrystalline niobium is studied in the temperature range 20–1000°C. The impurity content in the material is Ta<0.5 wt% and O₂<0.1 wt%. The acoustic split of the resonant frequency is found in the temperature range 60–180°C, which makes the determination of the Young’s modulus uncertain. Mechanisms behind the thermally stimulated splitting of an elastic wave and the behavior of the Young’s modulus over a wide temperature interval are discussed.