Internal friction peak associated with dislocations in Mg-0.6%Zr alloy

The internal friction （IF） of Mg-0.6%Zr alloy is measured in the present study and two IF peaks of （PI （97 ℃, 1 Hz） and P2 （230 ℃, 1Hz）） are found, respectively. It is shown that the novel P1 peak is frequency independent and the peak temperature increased with the increase of strain amplitude or heating rate. P1 peak could be repressed by the reheating-up measurements and represented by heat treatment. The mechanism of PI peak is clarified by optical microscope （OM） and transmission electron microscope （TEM） observation, and considered to be caused by the creation and expansion of dislocations during plastic deformation. The P2 peak is a thermally activated relaxation IF peak, and activation energy is 1.46 eV, which is caused by the relaxation of the grain boundaries in Mg-0.6%Zr alloy.