Hardening and microstructural reactions in high-temperature equal-channel angular pressed Mg-Nd-Gd-Zn-Zr alloy

The use of high-temperature (330 deg. C) equal-channel angular pressing (ECAP) is demonstrated to promote precipitation of a fine and uniform dispersion of the FCC β1 phase in an Mg-Nd-Gd-Zn-Zr alloy. Significantly, this process induces a hardening reaction in the alloy, where isothermal ageing at this temperature leads only to softening. The evolution of microstructure is characterized using transmission electron microscopy and scanning electron microscopy. The nucleation and growth of precipitates during the high-temperature ECAP are discussed. This research highlights a new approach to engineer precipitate microstructures via the application of severe plastic deformation so as to extend the property space of high-temperature Mg alloys.