Microstructures and mechanical properties of Mg–10Gd–6Y–2Zn–0.6Zr(wt. % ) alloy

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• 作者：Liang Zheng^a ; Chuming Liu ; ^a ; ^{cmLiu@mail.csu.edu.cn"" rel=""nofollow} ; Yingchun Wan^a ; Pingwang Yang^a ; Xin Shu^a
• 关键词：Microstructures ; Mechanical properties ; Mg– ; 10– ; Gd– ; 6Y– ; 2Zn– ; 0.6Zr alloy ; Strengthening models ; LPSO structure
• 刊名：Journal of Alloys and Compounds
• 出版年：2011
• 出版时间：1 September 2011
• 年：2011
• 卷：509
• 期：35
• 页码：8832-8839
• 全文大小：2786 K

文摘

Microstructures and tensile mechanical properties of Mg–10Gd–6Y–2Zn–0.6Zr alloy were systematically studied. Four phases were found in the as-cast specimen: α-Mg, Mg₃(GdYZn), Mg₁₂(GdY)Zn and Mg₂₄(GdYZn)₅. The long-period stacking order (LPSO) structure is found, which is the phase of Mg₁₂(GdY)Zn. The LPSO structure has two existing forms: lamellar structure in the inner grains and block-like structure at grain boundaries. 6H-type LPSO structure with a stacking sequence of ABCBCB′ is defined in homogenized specimen, where A and B′ layers are significantly enriched by Gd, Y and Zn. The ageing hardening behavior of as-extruded specimens at 200 °C has been investigated. The ultimate tensile strengths of the as-extruded and peak-aged alloys are 360 MPa and 432 MPa, and the elongations are 18 % and 5 % respectively. The effective strengthening models have been considered to predict the strength. The results suggested that the sub-micron metastable β′ phase was the main strengthening factor of the peak-aged alloy.