# Integrated Design of Aluminum-Containing High-entropy Refractory B2 Alloys with Synergy of High Strength and Ductility

**Authors:** Jie Qi, Xuesong Fan, Diego Ibarra Hoyos, Michael Widom, Peter K. Liaw, Joseph Poon  
**arXiv:** [2312.04708](https://arxiv.org/abs/2312.04708)  
**Date:** 2023-12-07  
**Summary page:** https://www.summarizepaper.com/en/paper/2312.04708v1/

## Key points

- Research focuses on integrated design of aluminum-containing high-entropy refractory B2 alloys for high strength and ductility
- Challenges in phase control and balancing strength and ductility in refractory high-entropy alloys (RHEAs)
- Use of integrated high-throughput machine learning and Monte Carlo simulations for phase-selection and predicting mechanical properties
- Development of aluminum-containing RHEAs with exceptional mechanical properties, including compressive yield strengths up to 1.6 GPa, fracture strains over 50%, and retention of high-temperature strength
- Tensile yield strength of 1.1 GPa with tension ductility of 6.3%
- Identification of valence-electron-count domain for alloy brittleness supported by density-functional theory explanations
- Insights into the influence of elements on atomic ordering and mechanical performance
- Experimental methodology involving suction-casting for compression testing, TEM sample preparation, machining rectangular bars for tensile testing, XRD, SEM analysis using diamond suspension and colloidal silica suspension
- Strategic blueprint for high-throughput alloy design and optimization of mechanical properties through innovative approaches combining machine learning, simulations, experimental techniques, and theoretical frameworks

## Summary

The research on integrated design of aluminum-containing high-entropy refractory B2 alloys with a synergy of high strength and ductility explores the potential of refractory high-entropy alloys (RHEAs) as promising high-temperature structural materials. The large compositional space of RHEAs presents significant challenges in phase control and achieving a balance between high strength and ductility. To address these challenges, the study pioneers the use of integrated high-throughput machine learning combined with Monte Carlo simulations to effectively navigate phase-selection and predict mechanical properties. The focus is on developing aluminum-containing RHEAs in single-phase ordered B2 alloys that demonstrate exceptional mechanical properties. These alloys exhibit compressive yield strengths up to 1.6 GPa, fracture strains exceeding 50 percent, and significant retention of high-temperature strength. Additionally, they showcase a tensile yield strength of 1.1 GPa with a tension ductility of 6.3 percent. Furthermore, the research identifies a valence-electron-count domain for alloy brittleness, supported by explanations from density-functional theory. Crucial insights into the influence of elements on atomic ordering and mechanical performance are provided, shedding light on fundamental principles that govern the mechanical properties of advanced structural alloys. In terms of experimental methodology, samples were suction-cast into copper molds to produce rod-shaped samples for compression testing and Transmission Electron Microscope (TEM) sample preparation, as well as rectangular bars machined into dog-bone shapes for tensile testing. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were employed to analyze polished samples prepared with diamond suspension and colloidal silica suspension. Overall, this work not only sets forth a strategic blueprint for high-throughput alloy design but also offers valuable insights into optimizing mechanical properties in advanced structural materials through innovative approaches combining machine learning, simulations, experimental techniques, and theoretical frameworks.