Grain Refining Mechanism of Carbon Inoculation on Mg-Al Alloy

doi:10.1007/s12204-012-1273-1

Abstract

Abstract: The processing parameters and refining mechanism of Mg-Al alloy treated with a newly developed carbon inoculant under different conditions were investigated experimentally in this work. Results show that the finest α-Mg grain in AZ91D alloy can be obtained after processing at about 740℃, and the average grain size of α-Mg grain decreases from about 180.4 to 85.6 μm by adding mass fraction win = 1% inoculant into melt. However, no evident refinement was achieved with excessive inoculant for Mn-free Mg-9Al alloy. Scanning electron microscope (SEM) photo, energy dispersive spectroscopy (EDS) analysis on the Mn-contained intermediate phase and differential scanning calorimetry (DSC) results indicate that Mn element plays an important role in the heterogeneous nucleation of α-Mg grain. In the early stage of solidification, Al-Mn-C compound particles formed on the surface of Al4C3 nano-particles should be the potential nuclei for primary α-Mg and probably responsible for the grain refinement achieved in the carbon inoculation process.

Key words: magnesium alloy| carbon inoculant| heterogeneous nucleation

摘要： The processing parameters and refining mechanism of Mg-Al alloy treated with a newly developed carbon inoculant under different conditions were investigated experimentally in this work. Results show that the finest α-Mg grain in AZ91D alloy can be obtained after processing at about 740℃, and the average grain size of α-Mg grain decreases from about 180.4 to 85.6 μm by adding mass fraction win = 1% inoculant into melt. However, no evident refinement was achieved with excessive inoculant for Mn-free Mg-9Al alloy. Scanning electron microscope (SEM) photo, energy dispersive spectroscopy (EDS) analysis on the Mn-contained intermediate phase and differential scanning calorimetry (DSC) results indicate that Mn element plays an important role in the heterogeneous nucleation of α-Mg grain. In the early stage of solidification, Al-Mn-C compound particles formed on the surface of Al4C3 nano-particles should be the potential nuclei for primary α-Mg and probably responsible for the grain refinement achieved in the carbon inoculation process.

关键词: magnesium alloy| carbon inoculant| heterogeneous nucleation

CLC Number:

LI Ke (李克), WANG Fei (王飞), WANG Qian (王倩), ZHOU Nai-geng (周耐根). Grain Refining Mechanism of Carbon Inoculation on Mg-Al Alloy[J]. Journal of shanghai Jiaotong University (Science), 2012, 17(3): 301-305.

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