Time filter

Source Type

Li B.,Central South University | Yang Z.,Central South University | Yang Z.,Guangzhou Iron and Steel Group | Yang X.,Central South University | And 2 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2015

The effects of Cu and Si on the lattice constant and electrical properties of Al-Si alloys were investigated by conductivity measurement, optical microscope, scanning electron microscope(SEM) and X-ray diffraction(XRD). The results show that as the mass fractions of Si and Cu increase, the conductivities of Al-Si alloys decrease, and the lattice disorder levels of the matrix increase. The effect of Cu on the conductivity of Al-Si alloys is much more significant than that of Si. After being heat treated (450 ℃×5 h+250 ℃×2 h), the lattice distortion levels of the Al matrix decrease significantly, the conductivities of Al-Si alloys improve obviously, and the increase of the conductivity is up to 32.36%. The influence mechanisms of Si and Cu on the conductivities of Al-Si alloys are different. The mass fraction of Si has little effect on Al lattice constant, and the effect of Si on conductivity of Al-Si alloys can be derived from the composite material resistivity calculation formula. And the effect of Cu can be deduced according to the deviation of Al lattice constant. © 2015, Central South University of Technology. All right reserved.


Li B.,Central South University | Yang Z.,Central South University | Yang Z.,Guangzhou Iron and Steel Group | Yang X.,Central South University | And 2 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2015

The effects of the content of Cu and Si elements as well as heat treatment on the lattice constant and electrical properties of Al-Si alloys were investigated by Wheatstone bridge conductivity measurement, optical microscope, scanning electron microscope and X-ray diffraction analysis. The results indicate that increasing the content of Si and Cu can decrease the conductivity of Al-Si alloy. When Si content is larger than its solubility in Al, variation of Si content has less influence on the lattice constant, and the resistivity of Al-Si alloy is determined by the volume percentage of Si. When Cu content is within its solubility in Al, the increase of Cu content would increase the distortion of aluminum lattice; consequently, the influence of Cu can be estimated according to Al lattice constant deviation. After heat treatment (450℃×5 h+250℃×2 h), the distortion of the matrix lattice decreases significantly, and the electrical conductivity of Al-Si alloys improves obviously with the increment up to 32%. © 2015, Science Press. All right reserved.


Shi X.-C.,Central South University | Yang Z.,Central South University | Yang Z.,Guangzhou Iron and Steel Group | Yang X.-Y.,Central South University | And 2 more authors.
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2015

Microstructure and properties of cast Al-7%Mg (mass fraction) alloy with different Ti contents were investigated by fluidity, hot crack and mechanical properties testing, combining with Optical Microscope (OM), Differential Scanning Calorimetry (DSC), Phase Diagram and Scanning Electron Microscope (SEM). The results show that grains of cast Al-7%Mg alloy are refined and equiaxed by adding Ti contents, with clear grain boundaries and increasing eutectic structures. Fluidity improves firstly and then reduces while hot tearing tendency decreases obviously with the increase of Ti contents. As a result, average flow length of the alloy with 0.2% Ti reaches 597 mm and the test samples do not present macroscopic crack when adding 0.5% Ti under experimental condition, respectively. Tensile strength, yield strength and elongation rate decrease after increasing first, and the best mechanical properties is obtained with Ti contents in the range of 0.2%~0.5%. Comprehensive analysis indicates that fluidity, hot crack and mechanical properties of cast Al-7%Mg alloy can achieve good condition with Ti contents in the range of 0.2%~0.5%, which contributes to the formation of components with complex shapes and special requirements. ©, 2015, Central South University. All right reserved.

Loading Guangzhou Iron and Steel Group collaborators
Loading Guangzhou Iron and Steel Group collaborators