Study Of Valent Electron Structure And Properties Of CuNiSi Alloy

Cu-Ni-Si Alloy is a typical reinforced alloy, and has both characteristics of the high strength and high conductivity. It has no magnetic compared with the lead frame which is used widely, thus it becomes the ideal material of Large Integrated Circuits, and has widely applied prospects, gradually becomes the focus of the research.This article bases on the theory of the solid and molecular experience electronic theory (EET). The structure calculating model of phase space covalence is built up, and the valence electron structure of pure metal crystals Cu and the solution alloy, such as the crystal cell of Cu-Si,Cu-Ni,Cu-Ni-Si, is calculated. It researches on the influence of the electrical conductivity,microhardness and microstructure of the CuNiSi alloy during the cold deformation and multistage aging process and the recrystallization behavior of the CuNiSi alloy due to the adding amount of the alloy element Ni and Si. Using transmission electron microscope focuses on the deeply study of the precipitation phase during CuNiSi alloy ageing process.The results of the research show that the strongest covalent electronic number of the pure metal crystals Cu and the solution alloy, such as the crystal cell of Cu-Si,Cu-Ni,Cu-Ni-Si, respectively is 0.375968,0.40125,0.42026,0.45722. It is visible to see that dissolving of the the alloy element Ni and Si can improve the atomic key gravity of the pure copper cell and strengthen the copper matrix. The better use of YuShi theory can provide the theoretical guidance for the composition design and processing of CuNiSi alloy.The cold deformation processing before aging can significantly improve the microhardness and the electrical conductive rate of CuNiSi alloy, for example, without the cold deformation of CuNiSi alloy after the aging of 450°C×0.5h, the microhardness and the electrical conductive rate respectively is 218HV and 32.1%IACS. The cold deformation of 80%, after the aging of 450°C×0.5h, the microhardness and the electrical conductive rate respectively is 242HV and 36.9%IACS. The comprehensive performances of alloy are significantly improved. The multi-stage ageing treatments can significantly improve the comprehensive performances of CuNiSi alloy, such as after the third age stage, the tensile strength and the electrical conductive rate, respectively achieves to 701MPa and 49.3%IACS, which is significantly higher than the 633MPa and 45.6%IACS of the second age stage and the comprehensive performance is much higher than a single aging process.The adding amount of the alloy element Ni and Si can significantly influence the recrystallization behavior of CuNiSi alloy. The higher amount of the alloy element Ni and Si, the process of the recrystallization process is slower, and the recrystallization temperature is higher.Transmission electron microscopy studies show that the precipitation phase is Ni₂Si during CuNiSi alloy ageing process. With the increasing of the ageing time and the ageing temperature, the precipitation phase of CuNiSi alloy has a trend to grow up, to make the strength of the alloy reducing and the electrical conductive rate increasing.