【摘要】 研究了方波脉冲电流对ZA27合金凝固组织的影响。结果表明脉冲电流的波形关系到谐波的频域及能量在其频域上的分布。脉冲电流诱发凝固系统处于振荡状态,脉冲电流的谐波的频域及能量分布影响到形成临界晶核所需的原子数。团簇表面熔体的振荡状态及润湿状态,原子的扩散激活能和整体熔体对振荡频率的响应。方波脉冲电流具有丰富的谐波,其高次谐波所引起的振荡的振幅衰减较慢,因而具有较好的孕育变质作用效果。更多还原

【Abstract】 Effect of rectangle wave pulse current on solidification of ZA27 alloy is studied. The results show that the wave pattern of pulse current determines on the frequency range of harmonic wave and the distribution of energy of pulse current among the frequency range. Imposed pulse current could induce the solidification system to oscillate. The frequency range and the relevant energy distribution of pulse current exert influence on the amount of atoms involved for forming critical nucleus, the surface states of clusters in melt, the oscillating state of melt on the surface of clusters, the active energy of atom diffusion, the frequency response of the resonance of bulk melt and the absorbability of the solidification system to the external work. Rectangle wave pulse current involves in rich harmonic waves, the amplitudes of induced oscillation of high order of harmonic waves are higher and reduce slowly, so it has better effect on inoculation and modification.更多还原