Microstructure evolution and thixoforming behavior of 7075 aluminum alloy in the semi-solid state prepared by RAP method

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• 作者：Jin-long Fu ; Kai-kun Wang ; Xiao-wei Li…
• 关键词：aluminum alloys ; microstructural evolution ; thixoforming grain coarsening ; segregation
• 刊名：International Journal of Minerals, Metallurgy, and Materials
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：23
• 期：12
• 页码：1404-1415
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Materials Science, general; Metallic Materials; Characterization and Evaluation of Materials; Ceramics, Glass, Composites, Natural Materials; Surfaces and Interfaces, Thin Films; Tribology, Corrosion
• 出版者：University of Science and Technology Beijing
• ISSN：1869-103X
• 卷排序：23

文摘

The effects of isothermal treatments on the microstructural evolution and coarsening rate of semi-solid 7075 aluminum alloy produced via the recrystallization and partial remelting (RAP) process were investigated. Samples of 7075 aluminum alloy were subjected to cold extrusion, and semi-solid treatment was carried out for 5–30 min at temperatures ranging from 580 to 605°C. A backward-extrusion experiment was conducted to investigate liquid segregation during the thixoforming process. The results revealed that obvious grain coarsening and spheroidization occurred during prolonged isothermal treatments. In addition, higher soaking temperatures promoted the spheroidization and coarsening process because of the increased liquid fraction and the melting of second phases. Segregation of the liquid phase caused by the difference in fluidity between the liquid and the solid phases was observed in different regions of the thixoformed specimens.