摘要
P modification has been widely used in Al-Si piston industry, but trace of Ca element has great influence on the P modification efficiency. In this work, it is found that primary Si can be heterogeneously nucleated by AlP in near eutectic AI-12.6Si alloy, but Ca element may destroy the P modification efficiency, whereas the addition of B can recover the P modification efficiency in near eutectic Al- 12.6Si alloy with high Ca containing. The microstructure transformation was related to the reaction of Ca, B, and AlP. According to the thermodynamic calculation, Ca may react with AlP and form Ca3P2 compound in Al-Si alloy, whereas, when B was added into the melt, AlP could be reformed. The reaction of Ca, B, and AlP can be shown as fol- lows： 2AlP ＋ 3Ca Ca3P2 ＋ 2AI; Ca3P2 ＋ 18B ＋ 2Al 3CAB6＋ 2ALP. In addition, with B added into the AI-12.6Si alloy with Ca and P addition, the mechanical properties were improved compared with single Ca and/or P addition.
P modification has been widely used in Al-Si piston industry, but trace of Ca element has great influence on the P modification efficiency. In this work, it is found that primary Si can be heterogeneously nucleated by AlP in near eutectic AI-12.6Si alloy, but Ca element may destroy the P modification efficiency, whereas the addition of B can recover the P modification efficiency in near eutectic Al- 12.6Si alloy with high Ca containing. The microstructure transformation was related to the reaction of Ca, B, and AlP. According to the thermodynamic calculation, Ca may react with AlP and form Ca3P2 compound in Al-Si alloy, whereas, when B was added into the melt, AlP could be reformed. The reaction of Ca, B, and AlP can be shown as fol- lows： 2AlP ＋ 3Ca Ca3P2 ＋ 2AI; Ca3P2 ＋ 18B ＋ 2Al 3CAB6＋ 2ALP. In addition, with B added into the AI-12.6Si alloy with Ca and P addition, the mechanical properties were improved compared with single Ca and/or P addition.
基金
financially supported by the National Natural Science Foundation of China (Nos. 51001065 and 51071097)
the National Key Basic Research and Development Plan (No. 2012CB825702)
the Shandong Province Foundation for Outstanding Youth Scientist (No. BS2009CL035)
the Independent Innovation Foundation of Shandong University (No. 2010TS081)
the Postdoctoral Independent Innovation Foundation of Shandong Province (No. 200901009)
