本研究使用 Mg97Y2Zn1 (at.%)合金作為基材，添加不同成分比例和粒徑尺寸之碳化矽(SiC)顆粒，以攪拌鑄造的方式製成鎂基複合材料。首先使用粒徑尺寸50 nm之SiC顆粒進行添加，分別添加1、3和5 wt.%。接著以分散性最佳的組別之成分比例作為添加不同粒徑時之添加參數，分別添加50 nm、1 μm和10 μm三種粒徑尺寸之SiC顆粒。最後觀察鎂基複合材料之顯微組織並進行機械性質測試。
　　研究結果顯示，使用不同添加量及粒徑之SiC顆粒製成之鎂基複材，其相組成均為α-Mg、Mg12Y1Zn1 及 SiC。透過顯微組織觀察發現，添加量5 wt.% 時會有最明顯的團聚現象，且添加量之增加會使晶界連續析出的Mg12Y1Zn1減少，而由晶粒析出的Mg12Y1Zn1變多。拉伸試驗結果顯示，Mg97Y2Zn1 合金之降伏強度和抗拉強度分別為66 MPa及126 MPa，伸長率為6.9 %。添加SiC顆粒之鎂基複材機械強度均有明顯提升，特別是添加1 wt.% 粒徑50 nm 之SiC顆粒時，由於具有最多由晶界連續析出之Mg12Y1Zn1使晶界強化且SiC顆粒散佈性最佳，故其降伏強度增加至101 MPa，抗拉強度增加至186 MPa，伸長率增加至10.2 %。

In this study, 1, 3 and 5 wt.% of SiC particles with the size of 50 nm were added to Mg97Y2Zn1 alloy by a stir-casting method. The best distribution of the SiC nano-particles was obtained with the addition of 1 wt.% SiC. Magnesium-based composites were fabricated with three different particle sizes (50 nm, 1 μm and 10 μm) of 1 wt.% of SiC to study the effect of particle size. Then, the microstructure of the composites was investigated by optical microscopy, scanning electron microscope and X-ray diffractometer. Mechanical properties of the composites were also studied.
The results show that the phase composition of magnesium-based composites are α-Mg, Mg12Y1Zn1 and SiC. Microstructural characterization of the composites show that the highest degree of agglomeration of SiC particles occurred when 5 wt.% of SiC was added. The amount of Mg12Y1Zn1 precipitates along grain boundary decreases when the amount of SiC particles increases. The 0.2% yield strength, ultimate strength and elongation of the as-cast Mg97Y2Zn1 alloy are 66 MPa, 126 MPa and 6.9 %, respectively. The mechanical strength of the composites increase; however, the elongation of the composite with 5 wt.% of SiC decreases due to the agglomeration of SiC particles. The composite with 1 wt.% of SiC having a particle size of 50 nm shows the best overall performance because of the largest amount of Mg12Y1Zn1 and lowest agglomeration of SiC particles.

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