Microstructure, mechanical properties and fracture behavior of peak-aged Mg-4Y-2Nd-1Gd alloys under different aging conditions

The morphology of precipitates and grain boundaries of peak-aged Mg-4Y-2Nd-1Gd alloys under different aging conditions were analyzed by transmission electron microscopy (TEM), and the mechanical properties and fracture behavior of the studied alloys both at room and elevated temperatures were investigated. The beta '' and beta' phases are the main precipitates of the alloys peak-aged at 200 degrees C and 225 degrees C, while the alloy peak-aged at 250 degrees C mainly consists of beta(1) and beta phases. Discussion on relationship between precipitates and mechanical properties, fracture behavior reveals that the precipitates' density, kind and arrangement are the dominating factors influencing the mechanical properties, and the combined influence of grain boundary structure and precipitation hardening determine the fracture mechanism of Mg-4Y-2Nd-1Gd alloys. (C) 2012 Elsevier B.V. All rights reserved.