Characterization of Hot-Extruded Mg–Gd–Y–Zn–Zr Alloy Containing a Novel Lamellar Structure and Related High Elevated-Temperature Mechanical Properties

다국어 초록 (Multilingual Abstract)

Hot extrusion was introduced to the Mg–10Gd–3Y–1.5Zn–0.5Zr alloy and microstructure evolution, texture configurationand elevated-temperature mechanical properties were investigated. The results show that the LPSO phase network-distributedalong grain boundaries in the as-cast and homogenized alloys is broken and elongated after extrusion, and is streamlined alongthe extrusion direction (ED). After extrusion, a completely recrystallized microstructure with equiaxed grains of ~ 10 μmis formed. The most notable feature in as-extruded alloy is numerous fine lamellar structures in DRXed grains, which wereidentified as basal stacking faults (SFs) with nano-spaced by TEM analysis. The < 0001 > //TD texture results in the hardorientation of most grains along ED. The extruded alloy exhibits excellent elevated-temperature mechanical properties(UTS/287 MPa and YS/218 MPa at 300 °C; UTS > 200 MPa at 350 °C) along ED, which is significantly higher than alloyswith similar composition or even higher rare earth content. The high elevated-temperature strength is mainly related to thefiber strengthening effect of streamline-distributed LPSO, the skeleton support effect of numerous SFs with nano spacing,and the texture strengthening effect of hard grain orientation.