Effects of Cu content on microstructure and mechanical properties of rheo-diecasting Al-6Zn-2Mg-xCu alloys  

作　　者：Zhi-guang Ding Sai-heng Hou Song Chen Ze-hua Liu Da-quan Li Jian Feng Fan Zhang Li-ming Peng 

机构地区：[1]National Engineering Research Center of Light Alloy Net Forming and Key State Laboratory of Metal Matrix Composites,School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China [2]General Research Institute for Nonferrous Metals,Beijing 101407,China

出　　处：《China Foundry》2022年第4期321-326,共6页中国铸造（英文版）

基　　金：The authors would like to thank the financial support from the National Key R&D Program of China(No.2016YFB0301003).

摘　　要：A systematic study on how Cu content affects the microstructure and mechanical properties of rheo-diecasting Al-6Zn-2Mg-xCu alloys during solution treatment and ageing heat treatment was conducted.The swirled enthalpy equilibrium device(SEED)was adopted to prepare the semi-solid slurry of Al-6Zn-2Mg-xCu alloys.The microstructure development and mechanical properties were studied using optical microscopy(OM),scanning electron microscopy(SEM),X-ray diffraction(XRD),differential scanning calorimetry(DSC),as well as hardness and tensile testing.The grain boundary and shape factor were calculated using image processing software(Image-Pro Plus 6.0).Results show that the alloys are composed of typical globular primaryα-Al grains,eutectic phases,and smaller secondaryα-Al grains.After solution and ageing heat treatment,the eutectic phases are dissolved into Al matrix when the Cu content is lower than 1.5wt.%,while some eutectic phases transform into Al_(2)CuMg(S)phases and remain at grain boundaries when Cu content reaches 2wt.%.T6 heat treatment significantly enhances the mechanical properties of rheo-diecasting Al-6Zn-2Mg-xCu alloys.When Cu concentration is 0.5wt.%-1.5wt.%,the ultimate tensile strength,yield strength and elongation of T6 treated alloys rise to around 500 MPa,420 MPa,and 18%,respectively.

关 键 词：Al-Zn-Mg-Cu alloy RHEO-DIECASTING Cu content mechanical properties heat treatment 

分 类 号：TG146.21[一般工业技术—材料科学与工程]