Partitioning of Ca to metastable precipitates in a Mg-rare earth alloy

IMPACT STATEMENT Both experimental investigation and first-principal calculation in a Mg-Nd-Y-Ca alloy revealed the partitioning of non-rare-earth element Ca to Mg-RE precipitates, suggesting the potential of Ca to enhance precipitation and strength. The potential effect of the element Ca on the precipitation behavior was investigated in an Mg-rare earth alloy. A combination of metastable beta ''' and beta ' precipitates was observed for the peak aging condition at 200 degrees C. Ca addition was found to have no significant effect on the precipitating phases and evolution sequence. Composition analysis showed that the Ca partitioned to both beta ''' and beta ' precipitate phases. First-principles calculations indicated that Ca partitions to the rare-earth sublattice in the precipitate phase. This finding suggests the potential of Ca to partially replace costly rare-earth elements in precipitation-hardened Mg-rare earth alloys.