Linear precipitate chains in Mg-2.4Gd-0.1Zr alloy after creep

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¯0_α〉) 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.