TEM Studies of In Situ Formation of MgO and Al4C3 During Thixomolding of AZ91 Magnesium Alloy Conducted in CO2

  • Ł. RogalEmail author
  • L. Litynska-Dobrzynska
  • Bogusław Baran
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)


MgO and Al4C3 compounds were produced in situ by reaction of CO2 with AZ91 alloy at semi-solid temperature range. Using modified magnesium injection molding, reactive carbon dioxide was introduced to hot zone of cylinder to conduct controlled oxidation reaction with partially melted Mg alloy. In result, nano-scale native MgO (30–50 nm) and small amount of Al4C3 carbide within eutectic mixture consisted of α(Mg) and β-Mg17Al12 were formed. Apart from eutectic obtained directly from liquid state, proeutectic magnesium solid solution α(Mg)p is crystallized. Homogeneously distributed α(Mg) globular grains (not melted during the process) with size 20–50 μm and volume 8–12% were also visible in the microstructure. Electron beam was aligned along [011] zone axis of MgO and [01-10] of αMg matrix. (11-1) planes of MgO were parallel to (0002) planes of the matrix. Orientation relationship was [011] MgO ║ [01-10] αMg and (11-1) MgO ║ (0002) αMg.


Thixomolding MgO Composites In situ 



The authors gratefully acknowledge the financial support by the National Centre for Research and Development, Grant No.: LIDER/007/151/L-5/13/NCBR/2014.


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© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • Ł. Rogal
    • 1
    Email author
  • L. Litynska-Dobrzynska
    • 1
  • Bogusław Baran
    • 1
  1. 1.Institute of Metallurgy and Materials Science, Polish Academy of SciencesKrakowPoland

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