Journal of Korea Foundry Society (한국주조공학회지)

Korea Foundry Society (한국주조공학회)
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A Study on Mechanical Characteristic of Hydrogen Charged Al-6.3Zn-2.4Mg Alloy

Al-6.3Zn-2.4Mg 합금의 수소충전에 따른 기계적 특성 연구

  • Kim, Dae-Hwan (Dept. of Metallurgical and Materials Engineering, Gyeongsang National University, Engineering Research Institute) ;
  • Choi, Tae-Young (Dept. of Metallurgical and Materials Engineering, Gyeongsang National University, Engineering Research Institute) ;
  • Shim, Sung-Young (Research Institute for Green Energy Convergence Technology) ;
  • Lim, Su-Gun (Dept. of Metallurgical and Materials Engineering, Gyeongsang National University, Engineering Research Institute)
  • 김대환 (경상대학교 금속재료공학과, 공학연구원) ;
  • 최태영 (경상대학교 금속재료공학과, 공학연구원) ;
  • 심성용 (그린에너지융합연구소) ;
  • 임수근 (경상대학교 금속재료공학과, 공학연구원)
  • Received : 2014.03.13
  • Accepted : 2014.04.24
  • Published : 2014.04.30
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Abstract

In this study, the extruded Al-6.3Zn-2.4Mg alloys were selected among the 7000 series aluminum alloys sensitive to hydrogen environment in order to examine the effects of both the aging conditions and the length of hydrogen charging period on the mechanical properties of the alloy. The specimens were aged for 24hours at $100^{\circ}C$ (under aging (UA)), $120^{\circ}C$ (peak aging (PA)), and $160^{\circ}C$ (over aging (OA)), respectively. Charging tests were performed at RT for 12, 24, 36 hours under potentiostatic conditions (-2000 mV vs (Ag/AgCl)) for 12, 24 and 36 hours in 1M $H_2SO_4$ and 0.1%$NH_4SCN$ solution. The fracture surface was examined by scanning electron microscopy (SEM). X-ray diffraction (XRD) pattern in peak aged sample was obtained before and after hydrogen charging from extruded Al-6.3Zn-2.4Mg alloys. The decreasing rate of tensile strength and elongation is represented in order of over aging < under aging < peak aging, and it is believed that the hydrogen recharge is more sensitive to elongation than tensile strength. The formation of $AlH_3$ in hydrogen charged Al-6.3Zn-2.4Mg alloys has been confirmed by X-ray diffraction studies.

Keywords

References

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