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Phase-field simulation of aluminium precipitation hardening processes

Christian Schwarze, Ruhr-Universität Bochum, Bochum, Germany

Reza Darvishi Kamachali, Ruhr-Universität Bochum, Bochum, Germany

Ingo Steinbach, Ruhr-Universität Bochum, Bochum, Germany

Time & Place
  • Date: 26.05.2015
  • Time:
  • Place: 2015 Bilateral Symposium of the Sino-German Cooperation Group Microstructure in Al Alloys & 1st Sino-German Symposium on Phase-Field Method and its Applications, Changsha, China

Abstract

Aluminium alloys importance on the broad fields of engineering is unbroken and therefore the understanding of complex hardening processes like precipitation is fundamental for guaranteeing required mechanical properties and applications. As it is been demonstrated recently spinodal decomposition precipitation was assumed 1 and implemented into open source phase-field software, OpenPhase 2. We make use of a recently developed dissipation model for interfaces 3,4 and replaced the phenomenological fourth-order gradient term of Cahn-Hilliard flux equation by a linear permeability term which gives a thermodynamically consistent theory of precipitation and ripening. Basic Al-Cu decomposition simulations are done but the model will be extended to predict elastic property effects on precipitation morphology. Furthermore, mechano-chemical coupling 5 is taken into account which features some new aspects of precipitation processes 6. For evaluation, different interface homogenization methods for elastic properties were implemented into our software 7. First precipitate growth simulations (metastable δ’) were done for a binary Al-Li alloy and will be extended to Al-Cu and Al-Li-Cu. Moreover, the growth behaviour and interaction of adjacent precipitates will be analyzed and compared to experimental results in the framework of the project. Forward looking, other processes like coherency loss effects during phase transformation and the influence of vacancies on the kinetic and structure of precipitates will be analyzed.

The financial support of German Research Foundation (DFG) under the project DA 1655/1-1 is greatly acknowledged.

References:

[1] K.T. Kashyap, P.G. Koppad, Bull. Mater. Sci. 34:1455 (2011)

[2] www.openphase.de

[3] I. Steinbach, L. Zhang, M. Plapp, Acta Mater. 60:2702 (2012)

[4] I. Steinbach, Ann. Rev. Mater. Res. 43:89 (2013)

[5] F.C. Larche, J.W. Cahn, Acta Metall. 30:1835 (1982)

[6] R. Darvishi Kamachali, E. Borukhovich, O. Shchyglo, I. Steinbach, Philos. Mag. Letters 93:680 (2013)

[7] K. Ammar, B. Appolaire, G. Cailletaud, S. Forest, European Journal of Computational Mechanics 18:485 (2009)

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