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用直接超声振动法处理了Al-17Si-xFe(x=2,3,4,5,质量分数)合金,利用光学显微镜、XRD及EDS等手段分析了传统铸造工艺和超声半固态成形合金的微观组织。结果表明,在无超声振动时,Fe含量为2%的铸态合金组织中的富Fe相以长针状β-Al5FeSi相为主,伴有少量板条状δ-Al4FeSi2相。随着Fe含量的增加,合金组织中长针状β-Al5FeSi相逐渐减少,针片状δ-Al4FeSi2相逐渐增多,Fe含量为5%时以粗大针片状δ-Al4FeSi2相为主。在液相线附近对上述不同Fe含量的合金熔体施加一定时间的超声振动后浇注到金属型,富Fe相均以块状和短条状δ-Al4FeSi2相为主,其晶粒平均等效直径在18～46μm之间,明显细化,此外还伴有少量针状β-Al5FeSi相。初步探讨了超声振动影响富Fe相形貌的作用机理。
Al-17Si-xFe (x = 2, 3, 4, 5, mass fraction) alloys were treated by direct ultrasonic vibration method. The microstructures of the conventional casting process and ultrasonic semi-solid alloy were analyzed by means of optical microscope, XRD and EDS organization. The results show that the Fe-rich phase in as-cast alloy with 2% Fe content is dominated by long-acicular β-Al5FeSi phase with a few lamellar δ-Al4FeSi2 phases in the absence of ultrasonic vibration. With the increase of Fe content, the long needle-shaped β-Al5FeSi phase in the alloy gradually decreases, and the needle-like δ-Al4FeSi2 phase increases gradually. When the content of Fe is 5%, coarse needle-shaped δ-Al4FeSi2 phase is dominant. Near the liquidus, the above-mentioned alloy with different Fe contents was subjected to ultrasonic vibrations for a certain period of time and then poured into the metal type. The Fe-rich phase was mainly composed of massive and short strip-shaped δ-Al4FeSi2 phases, and the average grain size Diameter 18 ~ 46μm, significantly refined, in addition to a small amount of needle-like β-Al5FeSi phase. The mechanism of ultrasonic vibration influencing the morphology of Fe-rich phase was discussed preliminarily.