In situ observation of ageing process and new morphologies of continuous precipitates in AZ91 magnesium alloy

An in situ observation of the precipitating process of γ-Mg17Al12 phase in die-cast AZ91 magnesium alloy, was carried out with a transmission electron microscope equipped with a heating stage maintained at 473 K for 8 h. In addition to the thin plate-shaped continuous precipitates, continuous precipitates with rod-shaped and the Potter orientation relationship were observed and analyzed with transmission electron microscopy including high-resolution transmission electron microscopy techniques. It was also observed firstly that there exist plate-shaped continuous precipitates with the Pitsch–Schrader orientation relationship in the die-cast AZ91 magnesium alloy.