A transmission electron microscopy investigation of defects in an Mg-Cu-Mn-Zn-Y damping alloy

A high number of dislocations have been observed in an as-cast high-damping Mg-3Cu-1Mn-2Zn-1Y (wt.%) alloy using transmission electron microscope (TEM). The majority of dislocations are distributed in parallel and uniform rows. Mg2Cu particles in the matrix are often found to be associated with a number of parallel dislocations. Twins containing stacking faults are also frequently observed. The formation of eutectic phases occurring during casting is followed by precipitation of secondary intermetallic phases in supersaturated alpha-Mg with alloying elements upon annealing. The observed defect structures provide useful experimental evidence supporting the previously proposed damping mechanism for Mg alloys. (C) 2011 Elsevier B. V. All rights reserved.