Estudo do comportamento mecânico da liga de alta entropia Hf-Nb-Ta-Zr por nanoindentação em dinâmica molecular

Abstract

In this master's thesis, the mechanical behavior of the high entropy alloy Hf-Nb- Ta-Zr was explored through atomistic simulations of molecular dynamics. The study focused on the mechanical response of the alloy with a body-centered cubic structure through the nanoindentation test. This structure was previously determined with the lowest energy structural equilibrium at 0 K. Subsequently, the alloy was subjected to nanoindentation tests considering the surfaces of the three main crystallographic planes (001), (011), and (111). The mechanical behavior of single crystals was studied in different scenarios. Initially, the physical and geometric parameters of the test were modified to analyze the possible existence of twins and the degree of hardness in different crystallographic directions. Thus, free-defect samples, indenter size, penetration speed, temperature, and crystalline orientation were considered. The analysis of the results suggests that the alloy has high hardness. Therefore, the classic dislocation mechanism does not seem to be this alloy's primary plastic deformation mechanism.