High-temperature internal friction in a pure tungsten single crystal, polycrystals with different grain sizes, and mechanically alloyed tungsten polycrystals was studied. Positron annihilation spectroscopy was used to prove that all studied materials contain a detectable amount of dislocations. Then, resonant ultrasound spectroscopy was applied to determine the internal friction evolution with temperature from room temperature up to 740 °C. For the pure tungsten samples, a sharp increase of internal friction was observed for temperatures above 470 °C (for the single crystal) or above 400 °C (for the polycrystals); the activation energy corresponding to this increase was the same as the activation energy for the ductile-to-brittle transition in tungsten reported in the literature. For the alloyed materials, direct observation of the onset of this relaxation mechanism was impossible due to additional effects resulting from the secondary phases in the material.

研究了纯钨单晶，不同晶粒尺寸的多晶和机械合金化的钨多晶的高温内摩擦。正电子ni没光谱用于证明所有研究的材料都包含可检测量的位错。然后，使用共振超声光谱法确定从室温到740°C的温度下内部摩擦的演变。对于纯钨样品，在高于470°C（对于单晶）或高于400°C（对于多晶）的温度下，观察到内部摩擦急剧增加。相应于该增加的活化能与文献中报道的钨中韧性到脆性转变的活化能相同。对于合金材料，