Influence of 5 at.%Al-Additions on the FCC to BCC Phase Transformation in CrFeNi Concentrated Alloys

A phase-field approach to study BCC precipitate evolution in FCC AlxCrFeNi medium entropy alloy including elastic effects

“…Their values were calculated using Thermo-Calc software with MOBHEA2 database and assuming the equilibrium composition of each phase. It was verified that the atomic mobilities are indeed almost constant over the considered concentration region and that the composition dependence of the diffusion in this quaternary alloys is well represented [7,8].…”

“…The next two terms represent the bulk chemical contribution with and , the free energy densities as a function of composition, as Gibbs energy functions of the FCC and BCC phase and a reference molar volume (difference in molar volumes of the different phases are considered through the eigenstrains in the elastic contribution). The Gibbs energy functions are obtained fitting higher order polynomial functions through a large set of Gibbs energy data calculated for the composition domain of interest using Thermo-Calc using the TCHEA2 database, as discussed in detail in previous papers [7,8].…”

“…The aim of this paper is to present initial results using a phase-field approach investigating microstructure evolution in the presence of elastic effects due to lattice misfit including CALPHAD data on the composition dependence of the thermodynamic and diffusion mobilities. Zuo et al [7,8] recently introduced a phase-field model for multicomponent precipitate growth and coarsening taking into account in a highly efficient way the CALPHAD Gibbs energy and diffusion mobility data for the quaternary alloy. In the current paper, elastic effects are added to this model description and initial simulations considering a single BCC precipitate in an FCC matrix are presented showing the effects of the elastic mismatch on precipitate shape, precipitate volume fraction and composition in the matrix as a function of time.…”

Phase-field study of elastic effects on precipitate evolution in (Al)0.05CrFeNi

“…Moelans [20,56] introduced a new type of interpolation function into the KKS formulation which guarantees thermodynamic consistency not only in grains and at interfaces, but also in multi-junctions. Based on these methods, a PF model was implemented for the AlCrFeNi system in our earlier work [51,52], with efficient coupling with the ThermoCalc TCHEA2 and TCMOBHEA2 thermodynamic and atomic mobility databases and accounting for local interfacial equilibrium at the interfaces. In the present work, this model is extended to consider the different elastic properties of the BCC and FCC phases appearing in the AlCrFeNi alloy.…”

“…The elastic properties are calculated through DFT calculations for the AlCrFeNi alloy. The PF model is based on our previous model [51,52], taking into account CALPHAD Gibbs energies and diffusion mobility data for the quaternary alloy in a highly efficient way. Elastic stress is added to this model using the micro-elasticity approach of Khachaturyan [34].…”