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Dynamic Compaction of Al 2 O 3 ‐ZrO 2 Compositions
Author(s) -
Tunaboylu Bahadir,
McKittrick Joanna,
Nellis W. J.,
Nutt Steven R.
Publication year - 1994
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1994.tb09764.x
Subject(s) - materials science , orthorhombic crystal system , compaction , monoclinic crystal system , composite material , slip (aerodynamics) , microstructure , crystallography , mineralogy , thermodynamics , crystal structure , chemistry , physics
Shock compaction of Al 2 O 3 ‐ZrO 3 binary and ternary powder compositions resulted in dense, one‐piece samples without visible cracks for pressures ≤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 α‐Al 2 O 3 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 ZrO 2 , 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 densificationhonding 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.