Dip-Test Internal Stress and the Composite Model of Creep Deformation


Article Preview

The composite model of plastic deformation is regarded as a realistic approximation of creep behaviour at elevated temperatures in a well-developed substructure consisting of dislocationdense subgrain boundaries (hard regions) and subgrain interiors (soft regions) with relatively low dislocation density. In the present contribution, the model is applied for an estimation of internal stresses that are experimentally measured by the dip-test technique. Two situations are considered within the model: (i) the density of moving dislocations is the same in both hard and soft regions and (ii) the density of moving dislocations is proportional to the local density in the respective region. The model enables to express the internal stress in terms of microstructural variables found by independent microscopic observations. It is shown that the magnitude of volume fraction of hard and soft region in the composite model has only a small effect on the value of internal stress.



Edited by:

Jaroslav Pokluda




F. Dobeš and A. Orlová, "Dip-Test Internal Stress and the Composite Model of Creep Deformation", Materials Science Forum, Vol. 482, pp. 291-294, 2005

Online since:

April 2005




[1] C.N. Ahlquist and W.D. Nix: Scripta Metall. Vol. 3 (1969), p.679.

[2] A.A. Solomon and W.D. Nix: Acta Metall. Vol. 18 (1970), p.863.

[3] H. Mughrabi: Mater. Sci. Eng. Vol. 85 (1987), p.15.

[4] W.D. Nix and B. Ilschner, in: P. Haasen, P. Gerold and V. Kostorz (Eds. ), Proc. 5 th Int. Conf. on the Strength of Metals and Alloys, Pergamon Press, Oxford, 1980, Vol. 3, p.1503.

[5] H. Mughrabi: Phys. Stat. Sol. (a) Vol. 104 (1987), p.107.

[6] R. Sedláček: Scripta Metall. Mater. Vol. 33 (1995), p.283.

[7] E. Nes: Acta Metall. Mater. Vol. 43 (1995), p.218.

[8] S.V. Raj and G.M. Pharr: Mater. Sci. Eng. Vol. 81 (1986), p.217.

[9] S. Takeuchi and A.S. Argon: J. Mater. Sci. Vol. 11 (1976), p.1542.