Atomic-scale analysis of nanoindentation behavior of high-entropy alloy

Abstract

Using molecular dynamics simulations, we study the elastic and plastic deformations of indentation in FeCrCuAlNi high-entropy alloy (HEA). The indentation tests are carried out using spherical rigid indenter to investigate the effects of high-entropy and severe lattice distortion in terms of shear strain, indentation force, surface morphology, defect structure, dislocation evolution and radial distribution function on the deformation processes. It can be found that when the indentation depth increases, the shear stress requires for the occurrence of the contact area between the indenter and the substrate increased, which is attributable to a higher probability to observe the dislocation evolution under a large indentation depth. The indentation test also shows that the equal element addition can significantly improve the mechanical properties of HEA compared with the conventional alloy. Based on the Hertzian fitting, the FeCrCuAlNi HEA has the Young's modulus of 161 GPa and hardness of 15.4 GPa, respectively. These values are higher than that of traditional metal materials, due to the low stacking fault energy and the dense atomic arrangement in the slip plane of HEA. In the plastic region, the Fe element causes the more stable crystal structure, much stronger than the Cu element, presumably resulted from a variety of crystal structures for Fe in the multicomponent FeCrCuAlNi alloy. Further, this effective strategy is used to accelerate the discovery of excellent mechanical properties of HEAs.

Understanding Deformation Behavior in Sintered Fe36Ni Alloy Through Nanoindentation Experiments and Molecular Dynamics Simulation

“…This is because the α‐(Fe, Ni) phase resists plastic deformation by reducing plane slippage and preventing interplanar dislocation as the plastic deformation of crystalline metals can be attributed to the slip dislocations. [ 44 ] Thus, the α‐(Fe, Ni) phase shows higher hardness than the γ‐(Ni, Fe) phase.…”

Structure, phase evolution and properties of Ta films deposited using hybrid high-power pulsed and DC magnetron co-sputtering

“…In particular, the hardness of tantalum film at DC-100 W was significantly lower than that reported in the literature because of its great sputtering atoms ability on the film surface, [19,24,26] which attributes to the grain growth of beta and the large surface roughness. [28][29][30] However, an abnormal hardness of Ta films with a value of 17.64 GPa was found at DC-30 W. Combining XRD (Fig. 2(b)) and SEM (Fig.…”

Microstructures and Properties of High‐Entropy Materials: Modeling, Simulation, and Experiments

“…The EAM potentials are capable of describing HEAs, such as FeNiCrCoCu HEAs. [ 44 ] However, due to the difficulty for establishing the atomic potential functions of the multiple‐element systems, the atomic potentials for HEAs are very scarce and limit the application of MD methods. The several other potentials in HEAs are proposed, including the EAM‐Morse hybrid potential function, [ 45 ] the modified embedded atom method (MEAM) potential function, [ 46 ] the average‐atom interatomic potential, [ 47 ] and the classic Lennard‐Jones (LJ) potential function.…”