Finite element simulations of microvoid growth due to selective oxidation in binary alloys

Pal, S and Kubair, DV (2006) Finite element simulations of microvoid growth due to selective oxidation in binary alloys. In: Modelling and Simulation in Materials Science and Engineering, 14 (7). pp. 1211-1223.

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Abstract

Selective oxidation induced void growth is observed in thermal barrier coating systems used in gas turbines. These voids occur at the interface between the bond coat (BC) and the thermally grown oxide (TGO) layer. In this paper we develop the modelling framework to simulate microvoid growth due to coupled diffusion and creeping in binary alloys. We have implemented the modelling framework into an existing finite element programme. The developed modelling framework and programme is used to simulate microvoid growth driven by selective oxidation in a binary \beta -NiAl alloy. Axisymmetric void growth due to the combined action of interdiffusion and creeping is simulated. The sharpness of the void and direction of creeping are considered as parameters in our study. Our simulations show that the voids dilate without any change in shape when creeping is equally likely in all the directions (isotropic). Void growth patterns similar to those observed in experiments are predicted when the creeping is restricted to occur only along the radial and tangential directions. A hemispherical void grows faster compared to a sharp void. The sharpness increases in the case of a sharp void and could lead to interactions with the neighbouring voids leading to spallation of the TGO layer as observed in experiments.

Item Type:	Journal Article
Publication:	Modelling and Simulation in Materials Science and Engineering
Publisher:	Institute of Physics
Additional Information:	Copyright of this article belongs to Institute of Physics.
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	16 May 2008
Last Modified:	19 Sep 2010 04:44
URI:	http://eprints.iisc.ac.in/id/eprint/13989

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