J Mater Sci Technol ›› 2012, Vol. 28 ›› Issue (6): 543-551.

• Light Weight Metals • Previous Articles     Next Articles

Microstructure and Mechanical Properties of an Extruded Mg-2Dy-0.5Zn Alloy

Guangli Bi1), Daqing Fang2), Weichuan Zhang1), Jothi Sudagar1), Qingxin Zhang1), Jianshe Lian1), Zhonghao Jiang1)   

  1. 1) Key Lab of Automobile Materials, Ministry of Education, College of Materials Science and Engineering, Jilin University, Nanling Campus, Changchun 130025, China
    2) College of Materials Science and Engineering, Taiyuan University of Science and Technology, Taiyuan 030024, China
  • Received:2011-07-22 Revised:2011-09-03 Online:2012-06-28 Published:2012-07-02
  • Contact: Zhonghao Jiang
  • Supported by:

    the National Natural Science Foundation of China (Grant No. 50771049)

Abstract: Microstructure and mechanical properties of an extruded Mg-2Dy-0.5Zn (at.%) alloy during isothermal ageing at 180 °C were investigated. Microstructure of the as-extruded alloy is mainly composed of α-Mg phase, 14H long period stacking order (LPSO) phase and small amounts of (Mg, Zn)xDy particle phases. During ageing, the 14H LPSO phase forms and develops and its volume fraction increases with increasing ageing time. Tensile test showed that the peak-aged alloy exhibits similar yield and ultimate tensile strengths and elongation to failure at room temperature, 100 °C and 200 °C, but excellent elevated temperature strengths at 300 °C as compared to the as-extruded and over-aged alloys. The analysis showed that the excellent elevated temperature strengths of the peak-aged alloy are attributed to the LPSO phase strengthening and the grain refinement strengthening, and the role of the LPSO strengthening is related to not only its amount, but also its morphology.

Key words: Magnesium, Mg-Dy-Zn alloy, Microstructure, Mechanical properties, Long period stacking ordered phase