Microstructure and Phase Control in Zr-Fe-Cr-Ni Alloys: Thermodynamic and Kinetic Aspects

Abstract

TEM investigations in Zr-Fe and Zr-Fe-Ni, Zr-Ni-Cr and Zr-Cr-Fe systems were performed to assess the second particles present in these alloys, either in quasi equilibrium conditions, or after quenching and annealing experiments. At equilibrium, Zr3Fe was found to dissolve Ni up to 12 at%. Ab initio computations provided formation enthalpies for several Zr-Fe compounds and showed that the Zr2Fe is metastable at low temperature. All of these data allowed us to extend the thermodynamic database ZIRCOBASE; very good agreement between the thermodynamic computations and the experimental evidences was obtained. Quenching and annealing experiments showed that Zr2Fe is formed for low quenching rates, while Zr3Fe is formed for higher quenching rates. Last, corrosion results in various conditions show that the influence of second phase particles volume fraction depends on the corroding atmosphere.

Progress report on the mechanical testing and thermal aging of Zr-bearing ferritic steels

“…Table 2 lists the comparisons between the calculated invariant reaction and experimental data. Table 3 compares the currently calculated enthalpies of formation of compounds in Fe-Zr system at 298K to the ab-initio calculated data [20,21], showing better agreement of the current modeling results than the previous Calphad modeling results [16][17][18][19]. The good agreements between the calculated results and all available experimental data or ab-initio calculated data validate the reliability of the current thermodynamic modeling.…”

“…Thermodynamic property data including measured mixing enthalpy of liquid at 1900K are available experimentally [16][17][18][19]. Additionally, ab-initio calculated enthalpies of compounds at 0K are available from the works of Ohodnicki et al [20] and Barberis et al [21].…”

“…Thirdly, previous thermodynamic modeling of the Fe-Zr system, if any, has been reviewed and compared with all available experimental data up to date. The Fe-Zr system was modeled by several authors [22][23][24], but their calculated enthalpies of compounds show large deviations from the ab-initio calculated results [20][21]. Attempts to use the existing Fe-Zr thermodynamic descriptions [22][23][24] to develop thermodynamic models for the Fe-Cr-Zr system encountered great difficulties.…”

“…Therefore, a new thermodynamic description of the Fe-Zr system was developed by taking into account both experimental data and ab-initio calculated results. Thermodynamic models and model parameters of phases in the Fe-Zr system were optimized in this work using experimental data in literature including phase equilibria [15], mixing enthalpy of liquid over 1900K [16][17][18][19], and the ab-initio calculated enthalpies of formation of compounds [20,21].…”

Zirconium Alloys: Properties and Characteristics

“…17 The need for a better control of the processing of the current alloys and the aim of finding new alloys and structures without too much experimental work have been a driving force for the modern trend in numerical simulation for material science. 19 The phase diagrams presented in this review were obtained according to this procedure. In that respect, a thermodynamic database for Zr alloys, called ZIRCOBASE, has been developed under the Calphad methodology.…”