摘要
Many investigations have revealed that transition of melt structure can effectively infl uence the fi nal solidifi cation microstructures.In this study,ultrasonic treatment was applied to Al-20%Si melt and Sr-modif ied Al-20%Si melt at 720℃(i.e.above liquidus of about 690℃)for 60 s,and then the melt was quickly quenched to room temperature.Experimental results show that ultrasonic treatment can ref ine the primary Si phase andα-Al of Al-20%Si alloy;strontium can make the morphology of Si phase spheroidized and refi ned as Sr addition changes the faceted growth characteristic of Si phase;however,the ref inement effect of ultrasonic treatment on the primary Si phase andα-Al is weakened by Sr addition.
Many investigations have revealed that transition of melt structure can effectively influence the final solidification microstructures. In this study, ultrasonic treatment was applied to AI-20%Si melt and Sr-modified AI-20%Si melt at 720 ℃ （i.e. above liquidus of about 690℃） for 60 s, and then the melt was quickly quenched to room temperature. Experimental results show that ultrasonic treatment can refine the primary Si phase and a-AI of AI-20%Si alloy; strontium can make the morphology of Si phase spheroidized and refined as Sr addition changes the faceted growth characteristic of Si phase; however, the refinement effect of ultrasonic treatment on the primary Si phase and α-AI is weakened by Sr addition.
基金
financially supported by the National Natural Science Foundation of China under contract No.50874022
关键词
金属材料
有色金属材料
有色轻金属材料
铝材料
ultrasonic treatment
nucleation rate
liquidus
strontium modification
quenching
