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The effect of pulse electric current with different density on solidification structures of hypoeutectic Al-7%Si, Al-10%Si and hypereutectic Al-22%Si alloys was studied. The shape and distribution of α-Al and Si were analysed.The experimental results showed that α- Al of Al-7% Si alloy is shortened when applied a pulse electric current during the solidification, and the microstructure turns from the obvious columnar crystal into rosette. After treatment with pulse electric current, the primary Si of Al-22%Si alloy was refined obviously. When the discharge voltage was 3kV, Si tended to gather at the edge of the sample and the primary α- Al appeared in this hypereutectic alloy. When the discharge voltage was 6kV, the primary Si was refined much more and distributes uniformly. Pulse electric current treatment had no evident effect on the approximate eutectic Al-10%Si alloy. The magnetic force was analysed under pulse electric current, and the reason of the phenomenon was discussed

A NiCrBSi coating was produced on a pure iron plate by laser cladding technology. Electric-magnetic compound field was applied in order to improve the quality of coating. The effect of electric-magnetic compound field on the microstructure and the phase composition of coating was investigated by OM and XRD, respectively. The results indicated that the phase composition of the coatings were γ-(Fe,Ni), Cr23C6, Cr7C3, CrB and Ni3B with and without electromagnetic field. Microstructural observation showed that the grains were refined obviously by electromagnetic stirring. The electromagnetic stirring could change the direction of the heat dissipation and changed the direction of the columnar crystal at the bottom of the coating. High qualitative coating without porosity were obtained under electromagnetic field.

The effects of final forging temperatures on deformability and structure evolution of high purity aluminum during multi-directional forging process were investigated. The results showed that increasing the initial forging temperature is beneficial for controlling the sample shape in the initial forging passes. Recrystallization during the initial forging passes improves the deformability of the sample in the following low-temperature forging processes. An X-shape fine grain zone is formed in the sample due to the inhomogeneous deformation of multi-directional forging process. When the forging pass is 6, the final forging temperature has an important influence on the grain size in the fine grain zone. The grain size decreases from 302 μm to 60 μm with the final forging temperature decreasing from 310 °C to 65 °C. The X-shape fine grain zone caused by the inhomogeneous deformation cannot be eliminated by increasing the final forging temperature (even higher than the recrystallization temperature of high purity aluminium).