Mechanical properties and constitutive behaviors of as-cast 7050 aluminum alloy from room temperature to above the solidus temperature  

作　　者：Qing-ling Bai Hong-xiang Li Qiang Du Ji-shan Zhang Lin-zhong Zhuang 

机构地区：[1]State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,Beijing 100083,China [2]SINTEF Materials and Chemistry,Trondheim,Norway

出　　处：《International Journal of Minerals,Metallurgy and Materials》2016年第8期949-958,共10页矿物冶金与材料学报（英文版）

基　　金：supported by the Fundamental Research Funds for the Central Universities of China(No.FRF-BR-15-078A);Beijing Laboratory of Metallic Materials and Processing for Modern Transportation,Specialized Research Fund for the Doctoral Program of Higher Education(No.20120006110019);the Opening Research Fund of the State Key Laboratory for Advanced Metals and Materials(Nos.2012Z-13,2014ZD-02,and 2015-ZD08)

摘　　要：The mechanical properties and constitutive behaviors of as-cast AA7050 in both the solid and semi-solid states were determined using the on-cooling and in situ solidification approaches, respectively. The results show that the strength in the solid state tends to increase with decreasing temperature. The strain rate plays an important role in the stress–strain behaviors at higher temperatures, whereas the influence becomes less pronounced and irregular when the temperature is less than 250°C. The experimental data were fitted to the extended Ludwik equation, which is suitable to describe the mechanical behavior of the materials in the as-cast state. In the semi-solid state, both the strength and ductility of the alloy are high near the solidus temperature and decrease drastically with decreasing solid fraction. As the solid fraction is less than 0.97, the maximum strength only slightly decreases, whereas the post-peak ductility begins to increase. The experimental data were fitted to the modified creep law, which is used to describe the mechanical behavior of semi-solid materials, to determine the equivalent parameter fGBWL, i.e., the fraction of grain boundaries covered by liquid phase.The mechanical properties and constitutive behaviors of as-cast AA7050 in both the solid and semi-solid states were determined using the on-cooling and in situ solidification approaches, respectively. The results show that the strength in the solid state tends to increase with decreasing temperature. The strain rate plays an important role in the stress–strain behaviors at higher temperatures, whereas the influence becomes less pronounced and irregular when the temperature is less than 250°C. The experimental data were fitted to the extended Ludwik equation, which is suitable to describe the mechanical behavior of the materials in the as-cast state. In the semi-solid state, both the strength and ductility of the alloy are high near the solidus temperature and decrease drastically with decreasing solid fraction. As the solid fraction is less than 0.97, the maximum strength only slightly decreases, whereas the post-peak ductility begins to increase. The experimental data were fitted to the modified creep law, which is used to describe the mechanical behavior of semi-solid materials, to determine the equivalent parameter fGBWL, i.e., the fraction of grain boundaries covered by liquid phase.

关 键 词：aluminum alloys mechanical properties constitutive relations fitting 

分 类 号：TG292[金属学及工艺—铸造]