Effects of Annealing on the Texture Development and Abnormal Grain Growth in a Commercial AZ31B Mg Alloy Sheet

상용 AZ31B Mg합금 판재의 어닐링에 따른 집합조직 변화 및 결정립 이상 성장

  • Yang, G.S. (Dept. of Advanced Materials Engineering, Chosun University) ;
  • Yoon, S.S. (Dept. of Metallurgical Engineering, Chosun University) ;
  • Jang, W.Y. (Dept. of Metallurgical Engineering, Chosun University) ;
  • Kang, J.W. (Dept. of Metallurgical Engineering, Chosun University)
  • 양권승 (조선대학교 신소재공학과) ;
  • 윤성식 (조선대학교 금속재료공학과) ;
  • 장우양 (조선대학교 금속재료공학과) ;
  • 강조원 (조선대학교 금속재료공학과)
  • Received : 2008.10.30
  • Accepted : 2008.11.12
  • Published : 2008.11.30

Abstract

In order to provide with fundamental data of the wrought Mg alloy for press forging, the effect of annealing temperature on the microstructure, texture development and tensile properties is studied in a commercial AZ31B Mg alloy sheet. Basal texture i.e. $(0001){\pm}5^{\circ}$[21$\bar{3}$0] is developed in a commercial AZ31B Mg sheet, and the texture is not changed considerably by annealing over $400^{\circ}C{\times}30min$, while (10$\bar{3}$0) component with high intensity can be observed due to abnormal grain growth. When the sheet is tensile-deformed with RD, $45^{\circ}$ and TD directions at room temperature, fracture strains are given by 25.8, 21.4 and 11.9% in the order of RD, $45^{\circ}$ and TD directions, respectively. With increasing annealing temperature up to $450^{\circ}C{\times}30min$, little change in mean grain size can be revealed by annealing below $300^{\circ}C{\times}30min$ but an abnormal grain growth, where some grains become significantly coarser than the rest, occurs by annealing above $400^{\circ}C{\times}30min$. The maximum tensile strain of around 25% is obtained by annealing below $300^{\circ}C{\times}30min$, but it is abruptly decreased to 16% by annealing above $400^{\circ}C{\times}30min$ owing to intergranular fracture of abnormal grown grains.

Keywords

References

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