Microstructural evolution of Mg-Al-Re alloy reinforced with alumina fibers

• 作者: Li Li Dejiang Li Xiaoqin Zeng Alan A.Luo Bin Hu Anil K.Sachdev Liangliang Gu Wenjiang Ding
• 来源期刊: 镁合金学报(英文)
• 学科: 工学
• 关键词: Mg-Al-RE Magnesium composite Slow shot high pressure die casting Microstructure CALPHAD AlxREy
• 年，卷（期）: 2020,（3）
• 页码范围: 565-577
• 页数: 13页
• 分类号: TG1

摘要

Few studies were reported on the phases'relationships of AE44(Mg-4.0Al-4.1RE-0.3Mn,wt.%)and its composites.In this work,AE44 alloy and Saffil(6-Al2O3)/AE44 Metal matrix composite(MMC)were both prepared by slow shot high pressure die casting(SS-HPDC)technology and their phase constitutions were all studied in detail using experimental techniques combined with CALPHAD(Calculation of Phase Diagram)modeling.The results revealed that the alloy consists of the a-Mg matrix,A1hRE3 intermetallic phase,and one trace phase AI3RE,while the composite contains five major phases:a-Mg,5-AI2O3,AI3RE,MgO and Mg2Si.and two trace phases of A12RE and AI11RE3,respectively.A1hRE3 is partly derived from ALRE,while A13RE is a product of the peritectoid reaction between the two precipitates.The presence of MgO and Mg2Si is due to the interfacial reaction between the SiO2 binder in the fiber preforms and the molten magnesium during infiltration.The use of SiO2 binder in the preform manufacturing was limited/minimized to reduce the MgO formation in the MMC casting process,which can be detrimental to the fatigue performance of the MMC materials.