Cu-Zn-Al 형상기억합금에서 기계적 성질에 미치는 결정형상의 영향에 관한 연구;주조조직과 재결정처리에 따른 기계적 성질과 형상기억능의 변화

Study on the Effect of Crystal Morphology on Mechanical Property in Cu-Zn-Al Shape Memory Alloy

  • 황승준 (고려대학교 대학원 금속공학과) ;
  • 이진형 (국민대학교 공과대학 금속공학과) ;
  • 홍종휘 (고려대학교 공과대학 금속공학과)
  • Hwang, Sung-Jun (Department of Metallurgical Engineering, Korea University) ;
  • Lee, Jin-Hyung (Department of Metallurgical Engineering, Kookmin University) ;
  • Hong, Jong-Hwi (Department of Metallurgical Engineering, Korea University)
  • 발행 : 1989.02.20

초록

The effect of heat treating temperature and ${\alpha}$ phase In the ${\beta}$ phase matrix were investigated for ${\beta}-CuZnAl$ shape memory alloys by tension test, fatigue test, and shape memory effect test. After heat treatment at $677^{\circ}C$, $750^{\circ}C$, $800^{\circ}C$ and $850^{\circ}C$ for 10 min. respectively, static fracture stress(${\sigma}_f$), fatigue fracture stress(${\tau}_{max}$) at $10^6$ cycle, and elongation(${\epsilon}_f$) was $24.2kg/mm^2$, $17.21kg/mm^2$ and 11.8%, respectively. As heat treating temperature decreased, fracture surfaces of the specimens were changed from the intergranular to the transgranular fracture mode. Especially, the a phase precipitated in the ${\beta}$ phase matrix had an effect on crack propagation and the fracture surface was characterized by dimple-like pattern when crack propagated in transgranular cracking mode. Precipitation of the ${\alpha}$ phase in the ${\beta}$ phase matrix lowered the transformation temperature by $10^{\circ}C$, and about 2.5 vol.% ${\alpha}$ phase did not affect the shape memory effect examined by the bending test.

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