Microstructure and mechanical properties of large-scale Mg-Gd-Y-Zn-Mn alloys prepared through semi-c

• 作 者: Kui Wang Jingfeng Wang Xiaoxu Dou Yuanding Huang Norbert Hort Sarkis Gavras Shijie Liu Yanwu Cai Jinxing Wang Fusheng Pan
• 机 构: National Engineering Research Center for Magnesium Alloys,College of Materials Science and Engineeri
• 出 处: 材料科学技术（英文版）
• 发表日期: 2020年17期
• 关键词: Mg-Gd-Y-Zn-Mn alloy Semi-continuous casting Thermal treatment Microstructure Mec

Large-scale Mg-8Gd-4Y-1Zn-Mn (wt.％) alloy ingot with a diameter of 315 mm and a length of 2410 mm was prepared through semi-continuous casting.Chemical composition,microstructure and mechanical properties at different locations of the samples with as-cast,T4 and T6 heat-treated states,respectively,were investigated.No obvious macro segregation has been detected in the high-quality alloy ingot.The main eutectic structures at all different locations are composed of α-Mg,Mg3 RE-type,Mg5RE-type and LPSO phases.At the edge of ingot,the unusual casting twins including 10-12 extension twins and 10-11 compression twins were observed due to the intensive internal stress.In T4 heat-treated alloy,the micro segregation was eliminated.The remained phases were α-Mg and LPSO phase.Combined with the remarkable age-hardening response,T6 samples exhibits improved mechanical properties at ambient temperature,which derives from the dense prismatic β'precipitates and profuse basal γ'precipitates.