Effects of grain size and temperature on mechanical response of nanocrystalline copper

Gupta

et al. 2023

MMMS

PurposeThe changes in tensile behavior of polycrystalline nanocopper lattice with changes in temperature, average grain size (AGS) and strain rate, have been explored. The existence of a critical AGS has also been observed which shows that the Hall–Petch relationship behaves inversely.Design/methodology/approachNanoscale deformation of polycrystalline nanocopper has been done in this study with the help of an embedded atom method (EAM) potential. Voronoi construction method has been employed for creating four polycrystals of nanocopper with different sizes. Statistical analysis has been used to examine the observations with emphasis on the polycrystal size effect on melting point temperature.FindingsThe study has found that the key stress values (i.e. elastic modulus, yield stress and ultimate tensile stress) are significantly influenced by the considered parameters. The increase in strain rate is observed to have an increasing impact on mechanical properties, whereas the increase in temperature degrades the mechanical properties. In-depth analysis of the deformation mechanism has been studied to deliver real-time visualization of grain boundary motion.Originality/valueThis study provides the relationship between required grain size variations for consecutive possible variations in mechanical properties and may help to reduce the trial processes in the synthesis of polycrystalline copper based on different temperatures and strain rates.

Section: Resultsmentioning

confidence: 99%

Grain size responsive uniaxial tensile behavior of polycrystalline nanocopper under different temperatures and strain rates

Gupta

et al. 2023

MMMS

“…Therefore, the damage is evenly distributed entirely the sample for the samples with the smaller GS, the NC HEA shows a stable plastic phase up to larger strains with no signs of localization, while the local damage occurs for the samples with the larger GS. Previously, Fang et al [43] reported that the stress of the NC Cu quickly dropped beyond the peak value before decreasing gradually when the GS was larger than 5 nm. Meanwhile, with the GS being less than 5 nm, the tensile stress decreased relatively stable after the peaking.…”

Section: Grain Size Effectsmentioning

confidence: 99%

Deformation mechanism and tensile properties of nanocrystalline CoCrCuFeNi high-entropy alloy: a molecular dynamics simulation study

Tran

2021

Phys. Scr.

For purpose of investigating the damage mechanism and tensile properties of the nanocrystalline CoCrCuFeNi high-entropy alloy, the tension experiment simulations were performed using the molecular dynamics method. The effects of the grain size, strain rate, experiment temperature, and percentage of components were considered in detail. By changing the simulated conditions of the tension experiment, the deformation and the grain growth of the nanocrystalline CoCrCuFeNi high-entropy alloy were mentioned and analyzed. The important mechanical factors such as phase transformation, stress-strain relation, shear strain, tensile strength, dislocation density, and von Mises stress were strongly influenced by changing the simulated conditions and deeply discussed.

“…The main difficulty encountered when applying those multi-phase concepts is to properly identify the properties of a grain boundary zone (or zones) and its volume fraction and morphology. Identification of those parameters and validation of the models are usually performed employing the molecular dynamics/statics simulations [16,17,18,2,19,20,4]. Occasionally, full-field FEM analyses are also conducted for this purpose, however, in such a case the refined constitutive description with scale effects is used [21].…”

Section: Introductionmentioning

confidence: 99%

Atomistic and mean-field estimates of effective stiffness tensor of nanocrystalline materials of cubic symmetry

Kowalczyk-Gajewska,

Maździarz

2019

Preprint

Anisotropic core-shell model of a nano-grained polycrystal, proposed recently for nanocrystalline copper, is applied to estimate elastic effective properties for a set of crystals of cubic symmetry. Materials selected for analysis differ in the lattice geometry (face-centered cubic vs. body-centered cubic) as well as the value of a Zener factor: a ratio of two shear moduli defining elastic anisotropy of a cubic crystal. The predictions are verified by means of the atomistic simulations. The dependence of the overall bulk and shear moduli on the average grain diameter is analysed. In the mean-field approach the thickness of the shell is specified by the cutoff radius of a corresponding atomistic potential, while the grain shell is isotropic and its properties are identified by molecular simulations performed for very small grains with approximately all atoms belonging to the grain boundary zone. It is shown that the core-shell model provides predictions of satisfactory qualitative and quantitative agreement with atomistic simulations. Performed study indicates that the variation of the bulk and shear moduli with the grain size changes qualitatively when the Zener anisotropy factor is smaller or greater than one.