Journal of Korea Foundry Society (한국주조공학회지)

Korea Foundry Society (한국주조공학회)
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Grain Refinement and Mechanical Properties of AM60 Mg Alloy by $CaCN_2$ Addition

Ca$CN_2$ 첨가에 의한 AM60 마그네슘 합금의 결정립 미세화 및 기계적 성질

  • Eom, Jeong-Pil (Research Center for Aircraft Parts Technology, Division of Materials Engineering, Gyeongsang National Univ.) ;
  • Jeong, Seong-Kyu (Dooray Air Metal Co., Ltd.) ;
  • Lim, Su-Geun (Research Center for Aircraft Parts Technology, Division of Materials Engineering, Gyeongsang National Univ.) ;
  • Shin, Hee-Taek (Kia Moter Ltd.) ;
  • Jeong, Deuk-Soo (Daedong Gear Ltd.)
  • 엄정필 (경상대학교 재료공학부, 항공기부품기술연구센터) ;
  • 정승규 (두레에어메탈(주)) ;
  • 임수근 (경상대학교 재료공학부, 항공기부품기술연구센터) ;
  • 신희택 (기아자동차(주)) ;
  • 정득수 (대동기어(주))
  • Published : 1998.08.20
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Abstract

Effects of $CaCN_2$ addition on the grain refinement in the AM60 magnesium ingots were investigated. The effects of the $CaCN_2$ are estimated with different inoculation temperatures, inoculation contents, and holding time to find out the optimum condition. AM60 alloy was melted in the low carbon steel crucible by cylindrical electric furnace under an argon atmosphere. The melting and casting apparatus is specially designed for magnesium alloys. The grain size of AM60 magnesium alloy decreased significantly with an increase in $CaCN_2$ content and, at 0.8 wt% $CaCN_2$ or more, grain size becomes constant at about $85 {\mu}m$. The optimum condition was obtained in the 0.8 wt% $CaCN_2$ for holding molten metal of 30 min. at the temperature of $710^{\circ}C$. The tensile properties of AM60 magnesium alloys were improved due to grain refinement by addition of $CaCN_2$. In the optimum condition, the yield strength, tensile strength and elongation were ${\sigma}_{0.2}=107 MPa$, ${\sigma}_{T.S}=234 MPa$ and e=14.2%. The variation of stress with strain obeyed the relationship of the ${\sigma}=K{\varepsilon}^n$. The strain-hardening exponent, n and strength coefficient, K obtained in the 0.8 wt% $CaCN_2$ added AM 60 magnesium alloy were n=0.21 and K=390 MPa.

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