Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Transformation Behavior on Heat Treatment Condition in Grain-Refined Cu-Zn-Al Shape Memory Alloy

결정립 미세화된 Cu-Zn-Al 형상기억합금의 열처리 조건에 따른 변태거동

  • Kang, J.W. (Dept. of Metallurgical Engineering, Chosun University) ;
  • Jang, W.Y. (Dept. of Metallurgical Engineering, Chosun University) ;
  • Yang, G.S. (Dept. of Materials Engineering, Chosun University)
  • 강조원 (조선대학교 공과대학 금속공학과) ;
  • 장우양 (조선대학교 공과대학 금속공학과) ;
  • 양권승 (조선대학교 공과대학 재료공학과)
  • Published : 1991.12.31
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Abstract

A small amount of misch metal and/or Zr was added as a dopant to 70.5wt----Cu-26wt----Zn-3.5wt----Al shape memory alloy in order to study the effect of grain refinement and heat treatments on the transformation behavior, stabilization of martensite, and shape memory ability. It was found that the addition of misch metal and Zr was very effective for reducing the grain size. The fracture mode has been changed from intergranular brittle fracture to ductile fracture with void formation and coalescence by the addition of misch metal and Zr. Aging of the ${\beta}$-phase decreases the $M_s$ temperature, but that of the martensite phase increases the $A_s$ temperature. The hysteresis of transformation temperature ${\Delta}T(A_s-M_s)$ has an increasing tendancy by grain refinement. The crystal structure of martensite was identified as monoclinic structure. As the grain size decreased, martensite stabilization more easily occured and the shape, memory ability has been reduced by the grain size refined.

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