Microstructure Evolution of Semisolid Mg-2Zn-0.5Y Alloy during Isothermal Heat Treatment

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• 作者：Liu Wei ; Yang Doudou ; Quan Gaofeng ; ^{quangf@gmail.com} ; Zhang Yingbo ; Yao Dandan
• 关键词：Mg-Zn-Y alloy ; semisolid ; isothermal heat treatment ; microstructure
• 刊名：Rare Metal Materials and Engineering
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：45
• 期：8
• 页码：1967-1972
• 全文大小：740 K
• 卷排序：45

文摘

Microstructure evolution of extruded Mg-2Zn-0.5Y (at%) alloy in semisolid isothermal heat treatment process was investigated. The results show that in the alloy there are α-Mg, Mg3-Zn6-Y1 (I-Phase) and Mg3-Zn3-Y2 (W-phase), and the average grain size of α-Mg is 7 μm. During the isothermal heat treatment at 793 K, the grains continue growing and no liquid phase appears until isothermal holding time reaches 4.0 min. With isothermal temperature rising and holding time increasing, solid α-Mg grains in the alloy gradually grow and are separated by liquid phases. Meanwhile, the liquid phase locating both at the grain boundaries and in the grain interior significantly increases. It is also found that at higher solid fractions, particle coarsening mechanism and solid particle remelting mechanism both play major roles. While at lower solid fractions, Ostwald ripening is the major mechanism and coalescence of adjacent particles could be still observed.