Influence of Sintering and Thermomechanical Treatment on Microstructure and Properties of W-Ni-Fe Alloys

  • M. Mitkov
  • W. A. Kaysser

Abstract

Densification and microstructural development during sintering of W-Ni and W-Fe-Ni alloys between 1100 and 1470°C were investigated. In solid state sintering densification and grain growth ceased at Ni or Ni/Fe contents above 0.15 wt.%. During liquid phase sintering, densification was enhanced by increasing the amount of lower melting additives. Dense liquid phase sintered samples were cold- or warm-worked to different degrees by rolling and rotation forging. The deformation of individual grains was measured. The distribution of the dislocation densities in individual grains was calculated from the shape and size of grains which formed during annealing of the worked samples in solid or partially liquid state. Dislocation densities of up to 1015 m-2 were deduced in the vicinity of contact areas of adjacent W grains after only a slight macroscopic deformation of the material by 5%. At higher degrees of deformation recrystallization of deformed initial W grains and their subsequent disintegration by the penetration of liquid phase lead to considerable grain refinement. The mechanisms of recrystallization, stress-induced boundary migration and melt penetration into the recrystallized fine grained materials are discussed.

Keywords

Contact Area Dislocation Density Liquid Film Cold Rolling Triple Junction 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 1989

Authors and Affiliations

  • M. Mitkov
    • 1
  • W. A. Kaysser
    • 1
    • 2
  1. 1.Institute Boris KidričBelgradeYugoslavia
  2. 2.Max-Planck-Institut für MetallforschungPulvermetallurgisches LaboratoriumStuttgart 80Deutschland

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