Effect Of Rectangle Wave Pulse Current On Solidification Structure Of Al-Cu Alloy

In this article, the effect of rectangle wave pulse current on ordinary and unidirectional solidification processing and structure of hypoeutectic and hypereutectic Al-Cu alloys were experimentally investigated with the equipment of pulse current and solidification in this lab.With the rectangle wave pulse current increasing, structure of hypoeutectic and hypereutectic Al-Cu alloys is refined on ordinary solidification. From magnetostrictive effect of solidification system, the atom's vibrational instability to eterogeneous nucleation, the reason is heterogeneous nucleation that is increased.Under action of pulse current, the drift of magnetic field gradient and the drift of curvature of magnetic line formed form the heterogeneity of magnetic field resection the migration Al³⁺ and Cu⁺ along the direction of magnetic field, and then promote the dominate growth of CuAl₂ Faceted crystals along the direction of magnetic field under the action of pulse current.With the rectangle wave pulse current frequency increasing, structure of hypoeutectic and hypereutectic Al-Cu alloys is refined on ordinary solidification. The reason is that rectangle wave pulse current have rich harmonic waves and highorderharmonic decreases slowly. For effective achievement is high, it is easy to gestation and deterioration.On the unidirectional solidification processing, with the rectangle wave pulse current increasing, hypoeutectic and hypereutectic Al-Cu alloys, dendrite distance is decreased. Hypoeutectic Al-Cu alloy loses its orientation. The reason is that current arise from Thomson and Peltier effect. Moreover, magnetostrictive effect arise from more shear strength. With the rectangle wave pulse current frequency increasing, dendrite's growth become 'v' shape. The result of magnetostrictive effect and cool velocity rise to the change of growth orientation.