Structure evolution of a WE43 Mg alloy submitted to different thermal treatments

The structure evolution of the WE43 Mg alloy during different thermal treatments is studied by differential scanning calorimetry (DSC), transmission electron microscopy (TEM) and positron annihilation spectroscopy (PAS). Isothermal annealings at different temperatures are made, with the aim to correlate the alloy's structure with its hardness response and to compare these treatments to the standard industrial T6 one (16 h at 250 degrees C). The highest hardening effect is obtained with a treatment at 210 degrees C with the formation of both beta and beta' phases. A residual amount of solute atoms into the matrix after each thermal treatment promotes the renucleation of beta and beta'. The standard T6 treatment mainly leads to the precipitation of the beta' phase, while the thermal treatment at 280 degrees C essentially promotes the formation of the equilibrium P phase. (c) 2007 Elsevier B.V. All rights reserved.