Ballistic Response of a FCC-B2 Eutectic AlCoCrFeNi2.1 High Entropy Alloy

• Published in: Journal of dynamic behavior of materials 2019-12, Vol.5 (4), p.495-503
• Main Authors: Choudhuri, Deep, Jannotti, Philip A., Muskeri, Saideep, Shukla, Shivakant, Gangireddy, Sindhura, Mukherjee, Sundeep, Schuster, Brian E., Lloyd, Jeffrey T., Mishra, Rajiv S.
• Format: Article
• Language: English
• Subjects: Chemistry and Materials Science; Domains; Edge dislocations; Eutectic alloys; Failure modes; High entropy alloys; Materials Science; Metallic Materials; Microstructure; Projectiles; Research Paper; Shear bands; Solid Mechanics; Tungsten carbide; Velocity
• ISSN: 2199-7446; 2199-7454
• DOI: 10.1007/s40870-019-00220-z

An AlCoCrFeNi 2.1 eutectic high entropy alloy (EHEA), comprising of FCC phase and a high volume fraction of plate and irregularly shaped BCC-ordered intermetallic B2 domains, was subjected to normal impact by spherical Tungsten–Carbide projectiles. Depending on projectile velocity, the impacted AlCoCrFeNi 2.1 plates were partially penetrated (at the lowest velocity of 803 m/s), plugged (intermediate velocity of 1159 m/s), and fully penetrated (highest velocity of 1388 m/s). Electron microscopy was utilized to characterize the residual damage or deformation features in the recovered specimens. Failure in the partially penetrated conditions was dominated by interfacial decohesion at the plate-like B2 and FCC interfaces. At higher velocities where plugging occurred, failure was dominated by crack formation in regions containing adiabatic shear band. These results indicated a transition in failure modes as a function of projectile velocities, where the FCC-B2 microstructure dominate failure at lower velocities, while such microstructural features do not influence dynamic failure at higher velocities.