|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Magnesium Technology 2017
||Development of Ultra-high Strength and Ductile Mg-Gd-Y-Zn-Zr Alloys by Extrusion with Forced-air Cooling
||Chao Xu, Taiki Nakata, Mingyi Zheng, Shigeharu Kamado
|On-Site Speaker (Planned)
Ultra-high strength Mg-8.2Gd-3.8Y-1Zn-0.4Zr (wt.%) alloys with moderate ductility were successfully developed in this study. The alloy was homogenized at 510oC, then cooled in furnace to ambient temperature or immediately quenched in warm water. Subsequently, hot extrusions at 450oC with and without forced-air cooling were carried out, followed by artificial ageing. The plate-shaped basal long period stacking ordered (LPSO) phases formed in the furnace cooled samples promote dynamic recrystallization (DRX) during extrusion, while the nanoscale basal stacking faults (SFs) formed in the quenched samples restrict the DRX. The forced-air cooling during extrusion refines the DRXed grain size and decreases the DRX ratio of the alloys. After peak-ageing, nanoscale β' phases densely precipitate on the prismatic planes of α-Mg matrix. The peak-aged sample extruded after the quenching and forced-air cooling exhibits ultra-high proof stress of 466 MPa, ultimate tensile strength of 514 MPa and moderate elongation to failure of 14.5%.