A high-strength Mg-6Zn-1Y-1Ca (wt%) alloy has been processed by a powder metallurgy route. Rapidly solidified powders with a particle size below 100 µm were used as a way for preventing formation of ternary MgZnCa compounds during subsequent extrusion at 250 °C. The microstructure of the extruded alloy consists of an ultrafine-grain magnesium matrix, with an average grain size of 444 nm, embedding a high volume fraction of fine I-phase particles aligned along the extrusion direction. The alloy combines an excellent ductility (14% of elongation to failure) with a high strength (ultimate strength of 469 MPa and yield stress of 461 MPa) at room temperature, mainly due to grain size refinement (around 70% of the yield stress). The strength is kept high up to 150 °C (yield stress of 279 MPa). Above this temperature, the mechanical strength falls to very low values but the ability to deform plastically is considerably enhanced, exhibiting superplastic behaviour from 200 to 350 °C, with a maximum elongation of 477% at 350 °C.

高强度Mg-6Zn-1Y-1Ca（wt％）合金已通过粉末冶金工艺进行了加工。使用粒度小于100 µm的快速固化粉末作为防止随后在250°C挤出过程中形成三元MgZnCa化合物的方法。挤压合金的微观结构由超细晶粒镁基体组成，平均晶粒尺寸为444 nm，嵌入了沿挤压方向排列的高体积分数的细I相颗粒。该合金在室温下具有出色的延展性（断裂伸长率的14％）和高强度（最终强度为469 MPa，屈服应力为461 MPa），这主要归因于晶粒尺寸的细化（屈服应力的70％左右） 。强度可保持高达150°C（屈服应力279 MPa）。高于这个温度，