Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

A fundamental base and model for the design and sintering optimisation of disc and ball-head shape AL2O3-ZrO2 FGM's

A thermo- elasto- viscoplastic model developed and adapted for the sintering of alumina- zirconia FGMs. With the model distribution of temperature, density, strain rates and displacements, normal (radial and axial) stresses and shear stresses can be obtained. The model uses analytical contribution as micro mechanical analysis and experimental feedback to validate the calculation results and to ensure the most adequate description of the materials state during and after processing.

The model was coupled with heat transfer and materials viscosity. Heating non-uniformity has been taking into account and instant temperature distributions were also obtained. The model was implemented for ABAQUS/Standard software for fully coupled thermal displacement analysis.

The materials properties have been collected from experiments and integrated into a special user subroutine. It is possible to adapt the model for other commercial software such as FEMLAB.

With the model, it is possible to evaluate critical stresses distribution, optimise processing route (temperature program, green density, gradient composition etc.) to obtain targeted properties. Also, a reverse task is possible - to calculate green part dimensions using the most desired parameters in final state. This is essential for the design and shaping of green bodies before sintering.

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Helsinki University of Technology - TKK
P.O. Box 6200
02015 Hut