Internal friction associated with the microstructural changes in an AZ91 magnesium alloy

Abstract

Temperature dependence of logarithmic decrement was measured in Mg-9Al-1Zn alloy. The developed internal friction peak was found while heating in the vicinity of 320 • C. Position and height of this peak in the temperature scale depends on the heating rate. Simultaneously microstructural observations were performed in the selected points of the temperature scale. SEM revealed discontinuous precipitates at lower temperature which converted at higher temperatures into continuous precipitates. Possible internal friction mechanism is discussed.