Synergistic effect of Sr and La on the microstructure and mechanical properties of A356.2 alloy

Autor: Yong-ning Wang, Weimin Zhao, Xinrong Li, Xingchuan Xia, Qiu Chuanrong, Jian Ding, Miao Sainan
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: Materials & Design, Vol 114, Iss, Pp 563-571 (2017)
ISSN: 0264-1275
Popis: In order to investigate the synergistic effect of Sr and La on the microstructure and mechanical properties of A356.2 alloy, Al-6Sr-7La master alloy was fabricated and its microstructure and phase compositions were investigated. The optimal percentage of Al-6Sr-7La in A356.2 alloy was obtained according to the evolution of microstructure and mechanical properties. What's more, to clearly access the refinement and modification performance of Al-6Sr-7La master alloy, untreated and traditionally treated A356.2 alloys (using 0.2 wt% Al-5Ti-1B as refiner and 0.2 wt% Al-10Sr as modifier, respectively) were used for comparison. The results showed that α-Al, Al4Sr and Al4La were the main phases in Al-6Sr-7La. In addition, the aluminum alloy with 0.5 wt% Al-6Sr-7La exhibited optimal microstructure and mechanical properties, with the secondary dendrite arm spacing (SDAS) decreasing to 17.9 μm and acicular-like eutectic silicon transforming to fibrous. Due to the improved microstructure, the ultimate tensile strength, yield strength and elongation of the alloy (with 0.5 wt% Al-6Sr-7La) increased to 228.15 MPa, 108.13 MPa and 11.92%, respectively, which are much better than that of traditionally treated A356.2 aluminum alloy. Finally, the grain refinement and modification mechanisms were discussed. Keywords: Al-6Sr-7La master alloy, Modification and grain refinement, Synergistic effect, Mechanical properties
Databáze: OpenAIRE
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