【摘要】 研究了方波脉冲电流对过共晶Al-50%Cu合金定向凝固组织的影响,主要考察了不同脉冲电流幅值和频率对合金枝晶间距和生长形态的作用效果。试验结果表明,随着脉冲电流幅值和频率增大,一次枝晶间距减小,主要是焦耳热的作用。此外,过共晶Al-50%Cu柱状晶随着脉冲电流的增加出现了V字型生长,失去定向凝固的方向性,这是由于脉冲磁压力和生长速度两方面作用的叠加导致柱状晶的生长方向发生改变的结果。更多还原

【Abstract】 The study was carried out to investigate the influence of square wave pulse current on the directional solidification structure of hypereutectic Al-50%Cu alloy and the effects of the amplitude and frequency of the pulse current on dendrite spacing and growing morphology were investigated. The experimental results show that the dendrite spacing reduces as the amplitude and frequency of the pulse current increase, and Joule heat takes the main role. Moreover, with the increasing of the current, the columnar crystals of hypereutectic Al-50%Cu start to grow in the shape of V, and the directionality of solidification disappears. It is actually the result of duple action of pulse magnetic force and growth rate that changes the growth direction of the columnar crystals.更多还原