Micromechanics reveal strain rate dependent transition between dislocation mechanisms in a dual phase high entropy alloy

• Main Authors: Kalácska, Szilvia, Sharma, Amit, Ramachandramoorthy, Rajaprakash, Vida, Ádám, Tropper, Florian, Pero, Renato, Frey, Damian, Maeder, Xavier, Michler, Johann, Ispánovity, Péter Dusán, Kermouche, Guillaume
• Format: Journal Article
• Language: English
• Published: 30-09-2024
• Subjects: Physics - Materials Science
• DOI: 10.48550/arxiv.2409.20368

An equimolar NiCoFeCrGa high entropy alloy having dual-phase homogeneous
components was studied, where the constituent phases exhibit distinct
mechanical properties. Micropillars with various diameters were created from
two differently heat treated samples, then they were compressed at slow strain
rates, that revealed the material's limited sensitivity to size. On the other
hand, increased strain rate sensitivity at high deformation speeds was
observed, that differs substantially depending on the phase composition of the
specimen. Dislocations within the two phases were studied by high resolution
transmission electron microscopy and high angular resolution electron
backscatter diffraction. The performed chemical analysis confirmed that slow
cooling during casting create Cr-rich precipitates, that have significant
impact on the global strength of the material.