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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 interface [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. For model verification case-study simulations of Ag-Cu decomposition were successful performed and the model was transposed to Al-Cu system. First Al-Cu decomposition simulations are already done but the model will be extended to predict elastic property effects on precipitation morphology. Furthermore, coupling between mechanical and chemical properties [5] will be taken into account which might feature some new aspects of precipitation process [6] as well as influence of vacancies on the kinetics and structure of precipitates.

Keywords: Phase-field model; Al alloys; Spinodal decomposition; Miscibility gap; Precipitation hardening

[1] K.T. Kashypa, 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)