Effect of Mass Ratio of Zn to Mg on Microstructure and Mechanical Properties of Hot-extruded Al-Zn-Mg-Sc Alloys
Author of the article:TANG Xiaoyi;YING Tao;YANG Jianying;LI Dejiang;ZENG Xiaoqin
Author's Workplace：School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Shanghai Jiao Tong University Baotou Institute of Material Research,Baotou 014000,China
Key Words：Al-Zn-Mg-Sc alloy Zn/Mg ratio hot extrusion microstructure mechanical properties
Abstract：The effect of Zn/Mg ratio on the microstructure and mechanical properties of Al-2 Mg-0.4 Sc,Al-5 Mg-0.4 Sc,Al-5 Mg-2 Zn-0.4 Sc,Al-5 Zn-2 Mg-0.4 Sc alloys extruded at 350℃were investigated by optical microscopy(OM),X-ray diffraction(XRD),scanning electron microscopy(SEM)and tensile testing under room temperature.The results show that the increase of Zn/Mg ratio had a refining effect on the as-cast grains.Dynamic recrystallization occurred after extrusion,and the grain size significantly decreased.However,the grain size of extruded do not decrease with the increase of Zn/Mg ratio.On the other hand,the increase of Zn/Mg ratio makes the number of the second phase of Mg32(Al,Zn)49 increase and shows a more obvious network structure.The yield strength of the extruded Al-Zn-Mg-Sc alloy increases with the increase of Zn/Mg ratio,mainly because of a large number of Al3 Sc particles and the second phase of fragmentation are distributed in the grain boundary in a network,so the second phase strengthening plays a leading role.
