[Transformation toughening] [electronic resource].

Published:: Washington, D.C. : United States. Dept. of Energy, 1993.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description:: Pages: (14 pages) : digital, PDF file
Additional Creators:: United States. Department of Energy and United States. Department of Energy. Office of Scientific and Technical Information

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Summary:

In NiAl, we have succeeded in determining the complete Ginzburg-Landau strain free energy function necessary to model the cubic to tetragonal martensite transformation in a sample of any size. We believe that this is the first time that the parameters of a Ginzburg-Landau functional and the complete strain spinodal for any three-dimensional displacive transformation were used in simulating the transformation near a crack tip under Mode I loading; the transformation pattern and toughening are different from standard transformation toughening theories. Furthermore, the strain spinodal has an approximately conical shape which can be specified by two material dependent experimentally accessible parameters, rather than the ellipsoidal shape in standard theories. Stress induced martensitic transformation in a polycrystalline sample of NiAl was simulated. In the ZrO[sub 2] system, first principles calculations to determine the semi-empirical potentials for simulating the cubic-tetragonal and tetragonal-monoclinic transformations have been started by doing a more elaborate total energy calculation.In the Al[sub 2]0[sub 3] system, we have discovered that the first principles calculations and semi-empirical potentials have just been completed byanother group in England which we will use instead to base our molecular dynamics simulations on.

Report Numbers:

E 1.99:doe/er/45318-6
doe/er/45318-6

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Published through SciTech Connect.
04/19/1993.
"doe/er/45318-6"
"DE93011805"
Rafa, M.J.
Connecticut Univ., Storrs, CT (United States)

Funding Information:

FG02-87ER45318

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