振动对ZL205A合金偏析组织及硬度的影响

为了解决ZL205A合金铸件产生偏析缺陷等问题，进一步明确振动对偏析组织及硬度的影响规律，采用电磁式振动台作为振动源，探究了振动频率、振幅、振动时间对合金偏析组织占比及硬度的影响情况。结果表明，振动频率在25~55 Hz内变化时，随着振动频率的增加，偏析组织占比呈现先减小、后增加的趋势，硬度呈现先增大、后减小的趋势；振幅由1 mm增加到4 mm的过程中，偏析组织占比逐渐减少并趋于稳定，硬度呈现先减小、后增大的趋势；振动时间由30 s增加至75 s时，偏析组织占比呈现增加趋势并最终趋于稳定，硬度呈现先减小、后增大的趋势。振动频率对合金偏析组织和硬度的影响最为显著，振动时间和振幅的影响次之，此外，偏析组织的析出也会影响合金硬度。研究结果为明确ZL205A合金在振动条件下凝固组织的变化规律、提高铸件质量提供了理论参考。

Effect of vibration on segregation structure and hardness of ZL205A alloy

In order to solve the problems of segregation defects in ZL205A alloy castings and clarify the influence of vibration on segregation structure and hardness, the electromagnetic vibration table was adopted as the vibration source to study the effects of vibration frequency, amplitude and time on segregation structure proportion and hardness of the alloy. The results show that the proportion of segregation structures decreases first and then increases, and the hardness increases first and then decreases with the increase of vibration frequency from 25 Hz to 55 Hz. When the vibration amplitude increases from 1 mm to 4 mm, the proportion of segregation structures decreases gradually and tends to be stable, and the hardness decreases first and then increases. With the increase of vibration time from 30 s to 75 s, the proportion of segregation structures increases and finally tends to be stable, and the hardness decreases first and then increases. Therefore, the vibration frequency has the most significant effect on segregation structure and hardness of the alloy, followed by time and amplitude. In addition, the precipitation of segregation structures also affects the hardness of the alloy. The results provide a theoretical reference for studying the change rule of solidification structure of ZL205Aalloy under vibration condition and for improving casting quality.