Predicting the temperature dependence of self-diffusion behavior in Ni-Cr alloys via molecular dynamics

Simonnin, Pauline; Schreiber, Daniel K.; Rosso, Kevin M.

doi:10.1016/j.mtcomm.2020.101982

Cited by 8 publications

(2 citation statements)

References 65 publications

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“…This scenario is born out by our simulations, which indicate that overall atomic mobility is reduced when Cr is added to the boundary, though Cr tends to migrate faster than Ni. This result is in contrast to MD studies of diffusivity in bulk Ni-Cr alloys, which found that increasing Cr concentrations led to higher Ni selfdiffusion rates [31]. Here, we find the opposite result, that generally overall transport is slowed by the addition of Cr.…”

Section: Discussioncontrasting

confidence: 99%

The effect of Cr alloying on defect migration at Ni grain boundaries

et al. 2022

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Mass transport along grain boundaries in alloys depends not only on the atomic structure of the boundary, but also its chemical make-up. In this work, we use molecular dynamics to examine the effect of Cr alloying on interstitial and vacancy-mediated transport at a variety of grain boundaries in Ni. We find that, in general, Cr tends to reduce the rate of mass transport, an effect which is greatest for interstitials at pure tilt boundaries. However, there are special scenarios in which it can greatly enhance atomic mobility. Cr tends to migrate faster than Ni, though again this depends on the structure of the grain boundary. Further, grain boundary mobility, which is sometimes pronounced for pure Ni grain boundaries, is eliminated on the time scales of our simulations when Cr is present. We conclude that the enhanced transport and grain boundary mobility often seen in this system in experimental studies is the result of non-equilibrium effects and is not intrinsic to the alloyed grain boundary. These results provide new insight into the role of grain boundary alloying on transport that can help in the interpretation of experimental results and the development of predictive models of materials evolution.

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Section: Discussioncontrasting

confidence: 99%

The effect of Cr alloying on defect migration at Ni grain boundaries

et al. 2022

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“…The repulsive potential has been extensively validated in various loading conditions, including tensile [27,28] and shear. [29] In recent years, especially in indentation simulation, [30][31][32] researchers have achieved good results in capturing stress responses, atomic deformations of Ni across different temperature ranges: [33][34][35][36][37]…”

Section: Simulation Models and Methodsmentioning

confidence: 99%

Temperature effect on nanotwinned Ni under nanoindentation using molecular dynamic simulation

He 何,

Xu 徐,

Ni 倪

2024

Chinese Phys. B

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The temperature effect on atomic deformation of nanotwinned Ni (nt-Ni) under localized nanoindentation is investigated in comparison with nanocrystalline Ni (nc-Ni) through molecular simulation. The nt-Ni exhibits enhanced critical load and hardness compared to nc-Ni, where perfect, stair-rod and Shockley dislocations are activated at (1$\mathop 1\limits^ -$1), ($\mathop 1\limits^ -$11) and (11$\mathop 1\limits^ -$) slip planes in nt-Ni compared to only Shockley dislocation nucleation at (1$\mathop 1\limits^ -$1) and ($\mathop 1\limits^ -$11) slip planes of nc-Ni. The nt-Ni exhibits a less significant indentation size effect in comparison with nc-Ni due to the dislocation slips hindrance of the twin boundary. The atomic deformation associated with the indentation size effect is investigated during dislocation transmission. Different from the decreasing partial slips parallel to the indenter surface in nc-Ni with increasing of temperature, the temperature-dependent atomic deformation of nt-Ni is closely related to the twin boundary: from the partial slips parallel to the twin boundary(~10K), to increased confined layer slips and decreased twin migration(300K~600K), to decreased confined layer slips and increased dislocation interaction of dislocation pinning and dissociation(900K~1200K). Dislocation density and atomic structure types through quantitative analysis are implemented to further reveal the above dislocation motion and atomic structure alteration. Our study helps to understand the temperature-dependent plasticity of twin boundary in nanotwinned material.

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