Influence of extrusion temperature on microstructure and mechanical behavior of duplex Mg-Li-Al-Sr alloy

JOURNAL OF ALLOYS AND COMPOUNDS

卷:750

Article

Yang, Yan^1,2,4  Xiong, Xiaoming¹  Su, Junfei¹  Peng, Xiaodong^1,2  Wen, Haiming³  Wei, Guobing¹  Pan, Fusheng^1,2  Lavernia, Enrique J.⁴ 

[1] Chongqing Univ, Sch Mat Sci & Engn, Chongqing 400044, Peoples R China

[2] Chongqing Univ, Natl Engn Res Ctr Magnesium Alloys, Chongqing 400044, Peoples R China

[3] Missouri Univ Sci & Technol, Dept Mat Sci & Engn, Rolla, MO 65409 USA

[4] Univ Calif Irvine, Dept Chem Engn & Mat Sci, Irvine, CA 92697 USA

关键词: Mg-Li alloy;    Extrusion temperature;    Microstructure;    Mechanical properties;    Dynamic recrystallization;   

DOI  :  10.1016/j.jallcom.2018.03.319

来源: Elsevier

【 摘 要 】

In this study, as-cast alloy Mg-9Li-3A1-2.5Sr (LAJ932) ingots were extruded at different temperatures using an extrusion ratio of 28, and the underlying microstructural evolution and mechanical behavior were investigated. The results show that grains in the extruded LAJ932 alloy are much finer than those in the as-cast one, which indicates that the microstructural evolution during extrusion is governed by dynamic recrystallization. With increasing extrusion temperature, the grain size of the extruded alloy increases, and the strength decreases whereas the elongation increases. The alloy extruded at 250 degrees C possesses the highest strength of 238 MPa with an elongation of 18.1%, whereas(1) the alloy extruded at 350 degrees C has the largest elongation of 21.6% with a strength of 208 MPa. The differences in microstructure characteristics between the alpha-Mg phase and beta-Li phase in the alloy extruded at 250 degrees C suggest that continuous dynamic recrystallization (CDRX) occurs in the alpha-Mg phase during extrusion whereas the microstructure evolution in beta-Li phase is governed by discontinuous dynamic recrystallization (DDRX). DDRX occurs in alpha-Mg phase to some extent and the fraction of DDRX grains in the alloys increases with increasing extrusion temperature. (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

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