A critical analysis and a recent improvement of the two-dimensional model for solution–precipitation creep: application to silicon nitride ceramics

Abstract

The step model is one of the most widely used models of solution–precipitation creep in polycrystalline ceramics with secondary glassy phases. However, it leads to unrealistic stress exponent values when two-dimensional step nucleation takes place at the grain boundaries. We present a modification of the original model of step nucleation that avoids such unreasonable values by considering in detail the precipitation (or solution) process. The modified model agrees with reported experimental results for ceramic systems in which it has been accepted that high-temperature plasticity occurs by solution–precipitation.

Acknowledgements

This work has been supported by the project MAT2000–0622. Fruitful discussions with Professor J. Philibert and Dr L. P. Kubin are greatly acknowledged. We are very grateful to Professor F. Wakai for his comments and suggestions and his effort to help us to publish this paper.

Notes

 Present address: Departamento de Física, Universidad de Extremadura, Avenida de Elvas sn, 08071 Badajoz, Spain.

Additional information

Notes on contributors

A. Domínguez-Rodríguez ‡

 Present address: Departamento de Física, Universidad de Extremadura, Avenida de Elvas sn, 08071 Badajoz, Spain.