电脉冲孕育处理Al-22Si合金衰退性的研究

Inoculation Fading of Electric Pulsed Modification (EPM) on Al-22Si Alloy

研究了电脉冲孕育处理后不同静置时间对Al-22Si合金凝固组织中初生相形态、大小、分布的影响。结果表明,电脉冲处理后立刻浇注对Al-22Si合金有较明显的变质作用,初生Si相形态由粗大板条状变为块状,其平均尺寸由153.15μm降至77.35μm,分布也较均匀;但电脉冲处理也存在着较明显的衰退性,即随着熔体静置时间的延长孕育效果逐渐消失,当静置时间为80min时,其组织形态与未经电脉冲处理的组织相似,其平均尺寸由77.35μm升至143.67μm。

Effects of holding time on morphology,size and distribution of primary Si in Al-22Si alloy treated by EPM have been described.The results indicate that the solidification structure of Al-22Si alloy has been obviously modified with the melt treated by electric pulse,in which the uniformly distributed primary Si is converted from coarse lath into bulky and its average size is decreased from 153.15 μm to 77.35 μm,however,the inoculation modification is faded with increasing holding time.The structure in the EPM treated alloy is similar with that of no-EPM treated alloy with holding for 80 min,increasing from 77.35 μm to 143.67 μm in average size.