Curie Transition of NC Nickel by Mechanical Spectroscopy and Magnetization Study

Mechanical spectroscopy measurement is performed to study the internal friction of nanocrystalline （NC） nickel with an average grain size of 23 nm from room temperature to 610 K. An internal friction peak is observed at about 550 K, which corresponds to the Curie transition process of the NC nickel according to the result of magnetization test. Moreover, the fact that the explained by an analytical model Curie temperature of NC nickel is based on the weakening of cohesive lower than that of coarse-grained nickel is energy.     

Internal Friction of Bend-Deformed Nanocrystalline Nickel by Mechanical Spectroscopy

Internal friction of nanocrystalline nickel is investigated by mechanical spectroscopy from 360 K to 120 K. Two relaxation peaks are found when nanocrystalline nickel is bent up to 10% strain at room temperature and fast cooling. However, these two peaks disappear when the sample is annealed at room temperature in vacuum for ten days. The occurrence and disappearance of the two relaxation peaks can be explained by the interactions of partial dislocations and point defects in nanocrystalline materials.