Low frequency peak of internal friction at α + α'Leftrightarrowα + β peretectical reaction in Nb-H systems

An internal friction peak about 80–90 °C, unknown earlier, and abnormal change of shear modulus (f = 0.5–3.0 Hz) are detected at α + α′ ↔ α + β peretectikal reaktion in Nb-H alloys containing 10–50 at. % H. Temperature hysteresis presense is noted in positions of such internal friction peak at heating or cooling. Shear modulus change pattern and maximum temperature do not depend on temperature in hydrogen concentration range in these alloys. It is in full accordance with Nb-H state diagram. However, the height of a peak increases as hydrogen content increases in alloys. When heating or cooling rate decreases, the height of a peak decreases as well, but moreover, it usually tends to some constant. It is suggested that internal friction peak nature is associated with α′/β phase boundary slipping. (orig.)