| Abstract |
| Effects of Ca addition on the microstructural refinement of the Mg2Si phase in Mg-Si alloy have been investigated by utilizing optical microscope, energy-dispersive spectrometer(EDS). scanning electron microscope(SEM), transmission electron microscope(TEM). X-ray diffraction analysis, and image analyser. As-cast microstructure of the alloys investigated consisted of α-Mg matrix and two types of Mg2Si; i.e.. chinese script type eutectic Mg2Si and polygon type primary Mg2Si. Addition of Ca refined the distribution of Mg2Si by providing heterogeneous nucleation sites for Mg2Si; e.g. mean size of Mg2Si is 18㎛ in Mg-2Si and 9㎛ in Mg-2Si-0.2Ca. These microstructural refinement of Mg2Si could be also obtained by increasing cooling rate. By selected area diffraction pattern, the Mg2Si phase-matrix orientation relationship was established. The orientation relationship between the Mg2Si phase and α-Mg matrix was determined as: [311]α-mg//[114]Mg2Si (011)α-Mg// (311)Mg2Si |
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| Key Words |
| Mg-Al-Si-Ca alloy, Refinement of Mg2Si, Effect of Ca addition, Chinese script type of Mg2Si |
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