Design of Fe36.29Cr28.9Ni26.15Cu4.17Ti1.67V2.48C0.46 HEA using a new criterion based on VEC: Microstructural study and multiscale mechanical response

The present work updated empirical parameter ranges with a high adjustment to the experimental results as obtained by the means of the exploratory data analysis (EDA) method. A new high entropy alloy with FCC structure reinforced by precipitation of intermetallic phases fabricated by vacuum-argon induction melting was designed and modeled. The main results showed that the valence electron concentration (VEC) is the predom-inant empirical phase prediction parameter in high entropy alloys and that the lattice packing factor is necessary to determine the presence of intermetallic phases effectively. Phase stability ranges based on VEC associated with the base crystal structures and the presence of intermetallics corroborated computationally by CALPHAD and experimentally were reported. The interdendritic zone proved to be a preferential precipitation zone with pre-cipitates of sigma, TiC, and gamma' phases. The gamma' phase showed a size difference between the dendritic and interdendritic zone associated with diffusive Ti mechanisms. The nanoscale mechanical response determined that dislocation creep and reinforcement in the interdendritic zone are predominant creep mechanisms that obtained an effective entanglement of the dislocations increasing the strain hardening coefficient. The mechanical response of the alloy obtained is superior to the average of the alloys with FCC structure. It maintains a high ductility that allows reaching an energy absorption and damage tolerance of 43.56 GPa% showing severe plastic slip lines being in the range of use for aerospace applications and hydrogen tanks.

Automated summary

The present work updates empirical parameter ranges and designs a new high entropy alloy with FCC structure reinforced by intermetallic phase precipitation. The main results show that valence electron concentration (VEC) and lattice packing factor are important in predicting phases and intermetallics effectively in high entropy alloys. The study reports phase stability ranges based on VEC computed by CALPHAD and validated experimentally. The interdendritic zone is found to be a preferential precipitation zone, with sigma, TiC, and gamma' phases observed. The alloy exhibits superior mechanical response and high ductility, making it suitable for aerospace applications and hydrogen tanks.