Proceedings of the KWS Conference (대한용접접합학회:학술대회논문집)

The Korean Welding and Joining Society (대한용접접합학회)
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THE JOINT CHARACTERISTICS OF FRICTION STIR WELDED AZ91D MAGNESIUM ALLOYS

  • Kim, Jong-Woong (Dept. of Advanced Materials Engineering, SungKyunKwan Univ.) ;
  • Lee, Won-Bae (Dept. of Advanced Materials Engineering, SungKyunKwan Univ.) ;
  • Yeon, Yun-Mo (Suwon Science College) ;
  • Jung, Seung-Boo (Dept. of Advanced Materials Engineering, SungKyunKwan Univ.)
  • Published : 2002.10.01
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Abstract

A study was carried out to grow an understanding of the microstructural development of friction stir welds on an AZ91D magnesium alloy, and to evaluate the mechanical properties of the welds. AZ91D plates with the thickness of 4mm were used, and the microstructural development of the weld zone was investigated using optical and scanning electron microscopes. Square butt welding joint with good quality was obtained at the conditions of under 187mm/min of travel speed with 1100 to 1250 rpm of tool rotation speed. The microstructure within the weld region consisted of fine equiaxed grains with no evidence of the original dendritic structure. The hardness tests showed slightly increased harness in the weld region, and the minimum hardness measured is in that of the parent material. Tensile strength of the weld zone was remarkably improved due to very fine recrystallized structure. XRD pattern of weld zone revealed the removal of $\beta$ intermetallic compounds, $Mg_{17}$Al$_{12}$, which had been distributed in the base metal.l.

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