Journal of Korea Foundry Society (한국주조공학회지)

Korea Foundry Society (한국주조공학회)
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Thixo-extrusion of Semi Solid 7075 Aluminum Alloys and Mechanical Properties of The Extrudates

반응고 7075 알루미늄 합금의 반용융 압출 및 압출재의 기계적 특성

  • Choi, Tae-Young (Dept. of Metallical and Materials Engineering, Gyeongsang National University) ;
  • Kim, Dae-Hwan (Dept. of Metallical and Materials Engineering, Gyeongsang National University) ;
  • Kim, Soo-Bae (Dept. of Metallical and Materials Engineering, Gyeongsang National University) ;
  • Shim, Sung-Young (Dept. of Metallical and Materials Engineering, Gyeongsang National University) ;
  • Lim, Su-Gun (Engineering Research Institute (Gyeongsang National University))
  • 최태영 (경상대학교 나노.신소재 공학부) ;
  • 김대환 (경상대학교 나노.신소재 공학부) ;
  • 김수배 (경상대학교 나노.신소재 공학부) ;
  • 심성용 (경상대학교 나노.신소재 공학부) ;
  • 임수근 (경상대학교 공학연구원)
  • Received : 2014.02.14
  • Accepted : 2014.06.09
  • Published : 2014.06.30
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Abstract

Thixo-extrusion of semi-solid 7075 aluminum alloy and the mechanical properties of its extrudates were investigated. The semisolid alloy was prepared by a cooling slope cast. In other to perform thixo-extrusion, semi-solid 7075 aluminum alloy billets were reheated at the reheating conditions reported in a previous study. The maximum extrusion pressure in thixo-extrusion was 615MPa. This was lower than that of conventional hot extrusion ($P_{max}=940MPa$) at the same extrusion conditions due to the increased fluidity of the alloy billet in the semi-solid state. The values of Rockwell hardness (scale B) at the extrusion direction of the as thixoextruded bar were 48~53HRB and the difference in Rockwell hardness between the transverse direction and the extrusion direction was 5HRB or less. The results show that thxio-extrusion of semi-solid 7075 Al alloy improves the workability and anisotropic with the extrusion direction compared with hot extrusion of the conventional alloy.

Keywords

References

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