High Temperature Deformation and Microstructural Features of TXA321 Magnesium Alloy: Correlations with Processing Map

Authors

  • Chalasani Dharmendra,

    1. Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
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  • Kamineni Pitcheswara Rao,

    Corresponding author
    1. Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
    • Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
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  • Yellapregada Venkata Rama Krishna Prasad,

    1. processingmaps.com (formerly at City University of Hong Kong), Kowloon, Hong Kong
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  • Norbert Hort,

    1. Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Magnesium Innovation Centre, Max-Planck-Straße 1, Geesthacht 21502, Germany
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  • Karl Ulrich Kainer

    1. Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Magnesium Innovation Centre, Max-Planck-Straße 1, Geesthacht 21502, Germany
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  • This work was supported by General Research Funding (Project #115108) from the Research Grants Council of the Hong Kong Special Administrative Region, China.

Abstract

The hot deformation of cast TXA321 alloy has been studied in the temperature range 300–500 °C and in the strain rate range 0.0003–10 s−1 by developing a processing map. The map exhibited four domains in the temperature and strain rate ranges: (1) 300–325 °C and 0.0003–0.001 s−1, (2) 325–430 °C and 0.001–0.04 s−1, (3) 430–500 °C and 0.01–0.5 s−1, and (4) 430–500 °C and 0.0003–0.002 s−1. The first three domains represent dynamic recrystallization, resulting in finer grain sizes in the first two domains and coarser in the third domain. In the fourth domain, the alloy exhibited grain boundary sliding resulting in intercrystalline cracking in tension and is not useful for its hot working. Two regimes of flow instability were identified at higher strain rates, one at temperatures <380 °C and the other at >480 °C.

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