Plastic deformation in nanoindentation of Alx(CuCrFeNi)1−x high entropy alloy

Abstract

The molecular dynamics approach is utilized to examine the deformation mechanism and evolutionary patterns of mechanical behavior in the Alx(CuCrFeNi)1−x high-entropy alloy (HEA) during nanoindentation. A comprehensive investigation is carried out on how temperature, grain size, and alloy composition impact the mechanical attributes and structural changes in the Alx(CuCrFeNi)1−x HEA (with x representing the molar ratio, x = 0.04–0.3). Alterations in the proportion of aluminum within the alloy content reveal a correlation wherein an increase in the Al percentage leads to a reduction in the indentation force. In terms of plastic deformation, the interplay between Al concentration, grain size, and temperature influences the conversion of local stress and shear strain into the bulk of the substrate, as evidenced by the presence of diverse slip bands. Additionally, the concentration of aluminum and larger grain sizes facilitate the extension of shear bands into the substrate, thereby augmenting the overall ductility of the alloys. In the realm of microstructure development, the movement of mobile prismatic dislocations within the substrate significantly contributes to the deformation process. Notably, the aluminum content governs the displacement of these dislocation rings into the substrate, while the growth of these rings is hindered by the grain size.