A new thermal-mechanical finite element model capable of taking into account changes in the specific volume during austenite to ferrite γ-α transformation during cooling has been developed. This model, coupled with any of the existing phase transformation models, allows simulation of the sample shortening due to both thermal contraction and the dilatometric effect. The solution is considered as a direct problem model for inverse calculations. The distance between predicted and measured sample elongations is formulated as the cost function for the inverse analysis. It has been shown that the random distribution of the appearing ferritic phase within the sample cross section results in more gentle changes in the sample elongations with time during cooling than that in the case of the conventional approach. This allowed achievement of satisfactory agreement between the experimental and predicted curves in the dilatometric test reflecting both the dilatometric effect and thermal contraction of the specimen during cooling through austenite-ferrite transformation temperatures.
Vol. 46, no. 1 (2006), pp. 147-154