Effect of ultrasonic vibration on Fe-containing intermetallic compounds of hypereutectic Al-Si alloys with high Fe content

超声振动对高铁含量过共晶铝硅合金中富铁相的影响(英文)

The Fe-containing intermetallic compounds with high melting point in hypereutectic Al-Si alloys can improve the heat resistance and wear resistance at elevated temperatures. However, the long needle-like Fe-containing compounds in the alloys produced by conventional casting process are detrimental to the strength of matrix. The effect of ultrasonic vibration （USV） on the morphology change of Fe-containing intermetallic compounds in the hypereutectic Al-17Si-xFe （x=2, 3, 4, 5） alloys was systematically studied. The results show that, the Fe-containing intermetallic compounds are mainly composed of long needle-like β-Al5FeSi phase with a small amount of plate-like δ-Al4FeSi2 phase in Al-17Si-2Fe alloy produced by conventional casting process. With the increase of Fe content from 2% to 5% in the alloys, the amount of plate-like or coarse needle-like δ-Al4FeSi2 phase increases while the amount of long needle-like β-Al5FeSi phases decreases. In Al-17Si-5Fe alloy, the Fe-containing intermetallic compounds exist mainly as coarse needle-like δ-Al4FeSi2 phase. After USV treatment, the Fe-containing compounds in the Al-17Si-xFe alloys are refined and exist mainly as δ-Al4FeSi2 particles, with average grain size ranging from 26 μm to 37 μm, and only a small amount of β-Al5FeSi phases remain. The mechanism of USV on the morphology of Fe-containing intermetallic compounds was also discussed.

铝硅合金中的高熔点富铁相可以提高合金的热稳定性及耐磨性,但传统铸造工艺下富铁相的长针状形态对基体强度有不利影响。研究超声处理对不同铁含量过共晶Al-17Si-xFe（x=2,3,4,5）合金中富铁相形态变化的影响。结果表明,在传统铸造工艺下,含铁量为2%的铸态合金组织中的富铁相主要由长针状β-Al5FeSi相以及少量片状δ-Al4FeSi2相组成。随着铁含量从2%增加到5%,合金组织中长针状β-Al5FeSi相逐渐减少,片状或粗大针片状δ-Al4FeSi2相逐渐增多。含铁量为5%时,合金组织以粗大针片状δ-Al4FeSi2相为主。经超声处理后,合金中富铁相被细化,主要以块状δ-Al4FeSi2相形式存在,并含有少量针状β-Al5FeSi相;δ相的平均晶粒尺寸在26~37μm之间,明显细化。初步探讨了超声处理对富铁相形态变化的作用机理。