In this paper we present and discuss phase equilibria in the quaternary Al–Cr–Fe–Ni and the quinary Al–Co–Cr–Fe–Ni alloy systems based on experimental data from DTA/DSC, SEM/EDS, and SEM/EBSD on as-cast and isothermally annealed samples. These data as well as literature data were used for developing a new Al–Co–Cr–Fe–Ni thermodynamic description by the CALPHAD approach. Considerable efforts in this direction have been made already and commercial databases for high entropy alloys are available, e.g., TCHEA4 and PanHEA. We focus on comparing our new thermodynamic database with computations using TCHEA4 for two section planes, i.e., quaternary Al_xCrFe₂Ni₂ and quinary Al_xCoCrFeNi, where x is the stochiometric coefficient. According to our new thermodynamic description a single-phase field BCC-B2 is stable over a wider temperature range in both section planes, giving rise to dual-phase microstructures along solid state phase transformation pathways. In the section plane Al_xCoCrFeNi the two-phase field BCC-B2 + σ predicted by the new database is stable between 600 and 800°C, while in TCHEA4 this phase field extends to nearly 1000°C. Furthermore, our new database showed that the solidification interval with primary BCC-B2 phase in quinary as well as quaternary section planes is narrow, being in a good agreement with presented micro-segregation measurements. Additionally, computed phase fields and phase-field boundaries in the quinary section plane correspond well to the experimental results reported in the literature.

在本文中，我们根据DTA / DSC，SEM / EDS和SEM / EBSD的实验数据，介绍并讨论了四元Al-Cr-Fe-Ni和五元Al-Co-Cr-Fe-Ni合金系统中的相平衡在铸态和等温退火的样品上。这些数据以及文献数据通过CALPHAD方法用于开发新的Al-Co-Cr-Fe-Ni热力学描述。已经在这个方向上做出了相当大的努力，并且可获得用于高熵合金的商业数据库，例如TCHEA4和PanHEA。我们专注于将我们的新热力学数据库与使用TCHEA4的两个截面（即四元Al）的计算进行比较_XCrFe ₂ Ni ₂和五元铝_XCoCrFeNi，其中x是化学计量系数。根据我们的新热力学描述，单相场BCC-B2在两个截面中都可在较宽的温度范围内保持稳定，从而沿固态相变途径产生了双相微结构。在剖面Al中_X新数据库预测的CoCrFeNi两相场BCC-B2 +σ在600至800°C之间稳定，而在TCHEA4中，该相场扩展到接近1000°C。此外，我们的新数据库显示，在五级和四级截面中，初生BCC-B2相的凝固间隔较窄，与现有的微观偏析测量结果非常吻合。另外，在五进制截面中计算出的相场和相场边界与文献报道的实验结果很好地对应。