Influence of Lanthanum on Solidification, Microstructure, and Mechanical Properties of Eutectic Al-Si Piston Alloy

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• 作者：R. Ahmad ; M. B. A. Asmael
• 刊名：Journal of Materials Engineering and Performance
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：25
• 期：7
• 页码：2799-2813
• 全文大小：2,748 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Characterization and Evaluation Materials
  Materials Science
  Tribology, Corrosion and Coatings
  Quality Control, Reliability, Safety and Risk
  Engineering Design
  
• 出版者：Springer New York
• ISSN：1544-1024
• 卷排序：25

文摘

The effects of Lanthanum (La) concentration on the solidification parameters of the α-Al, Al-Si, and Al-Cu phases and on the microstructure, tensile, and hardness properties of eutectic Al-Si-Cu-Mg alloy were systematically investigated. The solidification parameters were examined using computer-aided cooling curve thermal analysis (CA-CCTA). The cooling curve and microstructure analysis showed that La altered the Si structure. The nucleation and growth temperatures of eutectic Si decreased when 0.3 wt.% La was added, and a high depression temperature was obtained with 1.0 wt.% La. High amounts of La considerably modified the Si structure and decreased the area and aspect ratio by 69.9 and 51%, respectively. The thermal analysis result recorded a faster freezing time with the La addition and a 36% alteration in the secondary dendrite arm spacing. Two secondary or ternary La-rich intermetallic phases were formed with needle- and plate-like structures. Furthermore, the mechanical properties were investigated by hardness and tensile tests with different La concentrations. The addition of small amounts of La (0.1 wt.%) significantly improved the ultimate tensile strength and quality index of the Al-Si-Cu-Mg alloy. In addition, the hardness value of Al-11Si-Cu increased by 7-8% with the increasing amount of La added.Keywordsalloyslanthanummechanical propertiesmicrostructurethermal analysis