The microstructure of a Mg-2.4Gd-0.1Zr (at.%) alloy crept at 250 °C under 80 and 120 MPa has been investigated in this work. Under the influence of the applied stress, the precipitates are formed in chains along one direction (〈101¯0α〉) that is approximately normal to the applied stress direction. An unreported precipitate phase in Mg-Gd-based alloys, designated as βF′, is found to alternate with β′ phase in the precipitate chains. The βF′ phase has an irregular morphology, and is isomorphous with the Mg7Nd phase in binary Mg-Nd alloys. Although the β′ and βF′ both have three variants, the majority of β′ and βF′ precipitates in a precipitate chain keep only one orientation.
- Magnesium alloy