Design of eutectic high-entropy alloys in the Co-Cr-Ni-V-Ti-Al system using Scheil solidification path optimization

Abstract

The design strategy for eutectic high-entropy alloys (EHEA) is still in need of further exploration. This paper explores a new design approach using data computation, combining the simple mixing enthalpy method with a computed phase diagram approach based on a high-entropy alloy database. By calculating the thermodynamic empirical parameters of existing FCC/BCC-type eutectic alloy systems, the proportion range of alloy elements for eutectic design was narrowed. Ultimately, by analyzing the solidification path through the Scheil model, six eutectic compositions were obtained for the Co-Cr-Ni-Ti-V-Al alloy system that satisfy theoretical concepts. Microscopic characterization revealed that the actual alloy’s microstructure has only minor differences from the theoretically calculated results, with the main phase compositions of the alloys being FCC and BCC phases, aside from minor metal precipitates and third phases. However, significant differences were observed in the microstructures and mechanical properties of the six alloys. The research results demonstrate that this new design theory shortens the EHEA design cycle, enhances design accuracy and provides guidance for the eutectic design of target alloy systems.