DYNAMIC COMPACTION OF AL2O3-ZRO2 COMPOSITIONS


TUNABOYLU B. , MCKITTRICK J., NELLIS W., NUTT S.

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, cilt.77, sa.6, ss.1605-1612, 1994 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 77 Konu: 6
  • Basım Tarihi: 1994
  • Doi Numarası: 10.1111/j.1151-2916.1994.tb09764.x
  • Dergi Adı: JOURNAL OF THE AMERICAN CERAMIC SOCIETY
  • Sayfa Sayıları: ss.1605-1612

Özet

Shock compaction of Al2Os-ZrO2 binary and ternary powder compositions resulted in dense, one-piece samples without visible cracks for pressures less-than-or-equal-to 12.6 GPa. Dynamic pressures were achieved by using a 6.5-m-long two-stage gas gun. It is believed that plastic deformation by dislocation slip of alpha-Al2O3 partially accommodates the tensile stresses created during the release-of shock pressures. A fine and narrow particle size distribution is necessary to achieve high bulk densities, but the bulk structural integrity was not strongly related to the distribution. A high-pressure phase of ZrO2, which was formed from the monoclinic polymorph, was found at and above shock pressure of 6.3 GPa. No evidence of the orthorhombic cotunnite structure was observed. Compaction of glassy and submicrocrystalline rapidly solidified starting materials showed good structural integrity, although the bulk density was relatively low. It is not clear what the densification/bonding mechanism is in these materials, although it appears not to be plastic deformation. Microstructural analysis showed that fine and uniform microstructures are retained after compaction at appropriate dynamic pressures for all compositions, with some interparticle cohesion present.