The Effect of La-intermetallic Compounds on Tensile Properties of Al-15%Mg₂Si In-situ Composite

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• 作者：A. Akhlaghi^a ; M. Noghani^a ; ^{Mt_noghani@eng.ikiu.ac.ir" class="auth_mail" title="E-mail the corresponding author} ; M. Emamy^b
• 关键词：Al-15%Mg2Si in-situ composite ; Tensile properties ; La-intermetallic compounds.
• 刊名：Procedia Materials Science
• 出版年：2015
• 出版时间：2015
• 年：2015
• 卷：11
• 期：Complete
• 页码：55-60
• 全文大小：1494 K

文摘

In this work, an attempt was made to examine the effect of different La-intermetallic on the microstructure and tensile properties of Al-15%Mg₂Si metal matrix composite (MMC). The composite was made via in-situ process and characterized by optical microscope (OM), scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis. Microstructural characterization revealed that La changes not only the morphology of primary Mg₂Si particles from irregular to polyhedral and cubic shape. But also alter the eutectic Mg₂Si phase from flakes to rods and the volume fraction of Mg₂Si decreases while volume fraction of α-Al phase increases. La addition change the size of primary Mg₂Si from (∼17 μm) to (∼10 μm) and the size of eutectic Mg₂Si phase is reduced from more than 4.0 μm to less than 0.5 μm. This is mainly due to the formation of LaSi₂ phase during solidification, as detected by XRD analysis. Further results revealed that as the amount of fine La-intermetallic is increased, ultimate tensile strength (UTS) and elongation values of the MMC were also significantly increased. The fracture study of the composite showed the La-intermetallic changes the mode of fracture from brittle to more ductile.