Microstructure and mechanical properties of as-cast Mg–Al–Sn–Y–Nd alloy

Microstructure and mechanical properties of Mg–4Al–2Sn and Mg–4Al–2Sn–xY–yNd (x + y = 0.9 wt.%) alloys have been investigated. The microstructure of as-cast Mg–4Al–2Sn alloy consists of α-Mg, eutectic α-Mg + Mg17Al12, divorced eutectic Mg17Al12, and second phase Mg2Sn. Addition of Nd and Y results in fine plate-like Al2Nd and Al2Y phases which reduce the content of Mg17Al12 phase to improve the plasticity. Among the tested Mg–4Al–2Sn–xY–yNd alloys, Mg–4Al–2Sn–0.5Y–0.4Nd alloy represents the best mechanical properties. The tensile strength is increased from 220 to 225 MPa and elongation from 15.6% to 23.2%. Significant improvement of the plasticity is attributed to fine second precipitates and low anisotropy. The Mg–4Al–2Sn–0.5Y–0.4Nd alloy provides important potentials to develop high performance wrought magnesium alloys.

► Addition of Nd or/and Y decreases Mg17Al12 content and forms fine Al2RE phase.
► Single addition of Nd or Y can make the grain coarsen.
► UTS and ε are increased from 220 to 225 MPa and from 15.6% to 23.2%.