Achieving stable coherent pure Y nanoprecipitates in a Mg-Y alloy

The introduction of stable nanoprecipitates in magnesium (Mg) alloys is challenging. Herein, densely dispersed pure Y nanoprecipitates are successfully introduced into a binary Mg-Y alloy via in situ heating in a transmission electron microscope. Two reproducible orientation relationships between the nanoprecipitates and the Mg matrix are unraveled, which are confirmed to be energetically favorable by crystallographic matching calculations. The characteristic shape and size of the nanoprecipitates warrant the interfacial coherency to avoid easy coarsening. The nucleation and growth of the nanoprecipitates are further revealed at the atomic scale. Our findings provide new insights into strengthening strategies for Mg alloys. •Densely dispersed pure Y nanoprecipitates were introduced into a binary Mg-Y alloy.•The nanoprecipitates exhibit two energetically favorable ORs with the Mg matrix.•The shape and size of the nanoprecipitates well ensure the interfacial coherency.