J. Mater. Sci. Technol. ›› 2017, Vol. 33 ›› Issue (9): 1015-1022.DOI: 10.1016/j.jmst.2016.12.003

Special Issue: 2017腐蚀与防护专辑

• Orginal Article • Previous Articles     Next Articles

Effect of Sc and Zr additions on microstructures and corrosion behavior of Al-Cu-Mg-Sc-Zr alloys

Sun Fangfanga, Liu Nash Guirub, Li Qunyinga, Liu Enzuoac, He Chunnainac, Shi Chunshengac, Zhao Naiqinac*()   

  1. aSchool of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
    bDepartment of Mechanical, Materials and Aerospace Engineering, Illinois Institute of Technology, USA
    cTianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072, China
  • Received:2016-09-06 Revised:2016-10-31 Accepted:2016-12-19 Online:2017-09-20 Published:2017-10-16
  • Contact: Zhao Naiqin
  • About author:

    1 The authors contributed equally to this work.

Abstract:

The effects of adding the alloy element Sc to Al alloys on strengthening, recrystallization and modification of the grain microstructure have been investigated. The combination of Sc and Zr alloying not only produces a remarkable synergistic effect of inhibition of recrystallization and refinement of grain size but also substantially reduce the amount of high-cost additional Sc. In this work, the microstructures and corrosion behavior of a new type of Al-Cu-Mg-Sc-Zr alloy with Sc/Zr ratio of 1/2 were investigated. The experimental results showed that the Sc and Zr additions to Al-Cu-Mg alloy could strongly inhibit recrystallization, refine grain size, impede the segregation of Cu element along the grain boundary and increase the spacing of grain boundary precipitates. In addition, adding Sc and Zr to Al-Cu-Mg alloy effectively restricts the corrosion mechanism conversion associated with Al2CuMg particles, which resulted in the change of the cross-section morphology of inter-granular corrosion from an undercutting to an elliptical shape. The susceptibility to inter-granular corrosion was significantly decreased with increasing Sc and Zr additions to the Al-Cu-Mg alloy. The relationships between microstructures evolution and inter-granular corrosion mechanism of Al-Cu-Mg-Sc-Zr alloys were also discussed.

Key words: Aluminum alloy, Microstructure, Scandium, Inter-granular corrosion