Effect of cobalt addition on microstructure and mechanical properties of tungsten heavy alloys

  • U. Ravi Kiran
  • M. Sankaranarayana
  • G. V. S. Nageswara Rao
  • T. K. Nandy
Technical Paper


The present investigation attempts to study the microstructure and mechanical behaviour of tungsten heavy alloys with different cobalt content. Alloys with 2 and 3% cobalt were synthesized using liquid phase sintering technique. The alloys were then vacuum heat treated and finally swaged. Quantitative microstructural analyses were undertaken by determining tungsten grain size, contiguity of tungsten and volume fraction of the matrix etc. Tensile results showed that the alloy with 3% cobalt exhibited inferior properties as compared to 2% cobalt alloy. Detailed microstructural and fractographic analysis were undertaken in order to understand these trends. Work hardening analysis showed the double slope behaviour of the alloys, which could be attributed to change in deformation behaviour from single phase matrix to two phase aggregate. It was also concluded that higher cobalt alloys needed further optimization in terms of thermo-mechanical treatment in order to realize their full potential in terms of mechanical properties.


Tungsten heavy alloy Microstructure Mechanical properties Fractograph 



The work was supported by the finance provided by DRDO. The authors convey their sincere gratitude to Dr. S. V. Kamat, Distinguished Scientist and Director, DMRL for encouragement and kind permission to publish this work.


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Copyright information

© The Indian Institute of Metals - IIM 2017

Authors and Affiliations

  • U. Ravi Kiran
    • 1
  • M. Sankaranarayana
    • 1
  • G. V. S. Nageswara Rao
    • 2
  • T. K. Nandy
    • 1
  1. 1.Defence Metallurgical Research LaboratoryKanchanbagh, HyderabadIndia
  2. 2.National Institute of TechnologyWarangalIndia

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