Journal of Materials Science

, Volume 30, Issue 21, pp 5495–5501 | Cite as

Microstructure and mechanical properties relations for green bodies compacted from spray dried granules

  • D. C. C. Lam
  • K. Kusakari


Alumina granules from three binder systems were spray dried and pressed into bars at varied pressure. Granules are classified as strong, medium and weak as to reflect the different amount of poly(vinyl-butyral) binder and liquid paraffin plasticizer used in the binder system. Mechanical properties of the pressed bars were obtained from a four-point bend test and microstructures were examined using scanning electron microscopy SEM. Strengths and fracture toughnesses are found to increase as a function of compaction pressure, while the calculated effective flaw size is independent of the compaction pressure for all three granule types. Microstructural examination of fracture surfaces revealed that samples compacted at high pressure exhibited more transgranular fracture than samples compacted at low pressure. Evidently, higher pressure had increased the intergranular fracture resistance which correspondingly increased the fracture toughness of the pressed bars. For bars pressed from granules, green body strengths and toughnesses are strongly dependent on the cohesion between pressed granules and not on the effective processing flaw size.


Fracture Toughness Flaw Size Intergranular Fracture Green Body Liquid Paraffin 
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Copyright information

© Chapman & Hall 1995

Authors and Affiliations

  • D. C. C. Lam
    • 1
  • K. Kusakari
    • 2
  1. 1.Department of Mechanical EngineeringHong Kong University of Science and TechnologyKowloonHong Kong
  2. 2.Inorganic Materials Section, The 3rd Materials DepartmentHitachi Research LaboratoryIbaraki-kenJapan

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