Effect of elemental combination on friction stress and Hall-Petch relationship in face-centered cubic high / medium entropy alloys

Yoshida, Shinzo; Ikeuchi, Takuto; Bhattacharjee, Tilak; Bai, Yu; Shibata, Akinobu; Tsuji, Nobuhiro

doi:10.1016/j.actamat.2019.04.017

Cited by 219 publications

(46 citation statements)

References 54 publications

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“…The bonding profile between atoms affects the formation and movement of dislocations, therefore it plays an important role in the plastic deformation of materials. The element-element pair interactions [15] in HEAs are particularly interesting due to their complex chemical compositions. Generally speaking, if the interactions between different element pairs are of similar magnitudes, then it is easy for the atoms to change positions in the lattice since the energy difference is small.…”

Section: Investigation Of Effective Pair Interaction Parametersmentioning

confidence: 99%

Monte Carlo simulation of order-disorder transition in refractory high entropy alloys: A data-driven approach

Liu¹,

Zhang²,

Yin³

et al. 2021

Computational Materials Science

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High entropy alloys (HEAs) are a series of novel materials that demonstrate many exceptional mechanical properties. To understand the origin of these attractive properties, it is important to investigate the thermodynamics and elucidate the evolution of various chemical phases. In this work, we introduce a data-driven approach to construct the effective Hamiltonian and study the thermodynamics of HEAs through canonical Monte Carlo simulation. The main characteristic of our method is to use pairwise interactions between atoms as features and systematically improve the representativeness of the dataset using samples from Monte Carlo simulation. We find this method produces highly robust and accurate effective Hamiltonians that give less than 0.1 mRy test error for all the three refractory HEAs: MoNbTaW, MoNbTaVW, and MoNbTaTiW. Using replica exchange to speed up the MC simulation, we calculated the specific heats and short-range order parameters in a wide range of temperatures. For all the studied materials, we find there are two major order-disorder transitions occurring respectively at T 1 and T 2 , where T 1 is near room temperature but T 2 is much higher. We further demonstrate that the transition at T 1 is caused by W and Nb while the one at T 2 is caused by the other elements. By comparing with experiments, the results provide insight into the role of chemical ordering in the strength and ductility of HEAs.

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Section: Investigation Of Effective Pair Interaction Parametersmentioning

confidence: 99%

Monte Carlo simulation of order-disorder transition in refractory high entropy alloys: A data-driven approach

Liu¹,

Zhang²,

Yin³

et al. 2021

Computational Materials Science

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show abstract

“…[ 15 ] However, in HECs there are no solute or solvent atoms as all of the cations are equimolar. Mean field theory utilizing the solid solution strengthening concept has had some success in predicting yield strength and activation volume in HEAs, [ 16 ] and other work highlights the importance of element interaction [ 17 ] and interplanar potential randomness. [ 18 ] Atomic scale DFT modeling is a powerful tool to quantify these effects and provides atomic scale details.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Hardness in High‐Entropy Carbides through Atomic Randomness

Wang

Csanádi

Zhang

et al. 2020

Advcd Theory and Sims

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High‐entropy carbides (HECs) are of great interest as they are promising candidates for ultra‐high‐temperature and high‐hardness applications. To discover carbides with enhanced yield strength and hardness, mechanism‐based design approaches are needed. In this study, dislocation core atomic randomness as a mechanism for hardness enhancement is proposed, in which the random interactions between different elements at a dislocation core make it more difficult for the dislocation to slip. The Peierls stress of an a/2false⟨11¯0false⟩false{110false} edge dislocation is calculated based on density functional theory, in which atomic randomness is increased by increasing the number of elements at the dislocation core. The results show that the Peierls stress statistically increases with increasing number of elements, indicating that incorporating more elements is likely to produce higher hardness. Based on this guiding principle, three eight‐cation HECs are fabricated (Ti,Zr,Hf,V,Nb,Ta,X,Y)C (X,Y = Mo,W, Cr,Mo, or Cr,W), the composition of which is guided by ab initio calculations of their formation enthalpy and entropy forming ability. The single‐phase dense ceramics all show high nanoindentation hardness of around 40 GPa. The random interactions between different elements at a dislocation core provide a mechanism for improving the hardness of structural ceramics.

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“…It is speculate that increasing Cr concentration while maintaining the TWIP or TRIP effects through adjusting Co concentration may lead to high yield strength and high ductility simultaneously. Recently, there are some experiments showing that when compared to the CrCoNi MEA, the Cr40Co20Ni40 or Cr45Ni27.5Co27.5 alloys show higher yield strengths while maintaining similar levels of ductility [47,72,73]. However, one should be aware of the fact that Cr decreases the SFE faster than Co, which can cause higher numbers of thermally induced twin boundaries in the microstructures prior plasticity test, as well as promote the early presence of SFs at small strains, these factors also contribute to a higher yield strength.…”

Section: (Ii) Route 2 Towards Low-co High-cr Alloys;mentioning

confidence: 99%

Designing Transformation-Induced Plasticity and Twinning-Induced Plasticity Cr-Co-Ni Medium Entropy Alloys: Theory and Experiment

Yang

Tian

et al. 2020

SSRN Journal

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In order to efficiently explore the nearly infinite composition space in multicomponent solid solution alloys, it is important to establish predictive design strategies and use computation-aided methods. In the present work, we demonstrated the density functional theory calculations informed design routes for realizing transformation-induced plasticity (TRIP) and twinning-induced plasticity (TWIP) in Cr-Co-Ni medium entropy alloys (MEAs). We systematically studied the effects of magnetism and chemical composition on the generalized stacking fault energy surface (-surface) and showed that both chemistry and the coupled magnetic state strongly affect the -surface, consequently, the primary deformation modes. Based on the calculated effective energy barriers for the competing deformation modes, we constructed composition and magnetism dependent deformation maps at both room and cryogenic temperatures. Accordingly, we proposed various design routes for achieving desired primary deformation modes in the ternary Cr-Co-Ni alloys. The deformation mechanisms predicted by our theoretical models are in nice agreement with available experimental observations in literature. Furthermore, we fabricated two non-equiatomic Cr-Co-Ni MEAs possessing the designed TWIP and TRIP effects, showing excellent combinations of tensile strength and ductility. Corresponding authors: a Song Lu, songlu@kth.se b Yanzhong Tian,

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Effect of elemental combination on friction stress and Hall-Petch relationship in face-centered cubic high / medium entropy alloys

Cited by 219 publications

References 54 publications

Monte Carlo simulation of order-disorder transition in refractory high entropy alloys: A data-driven approach

Monte Carlo simulation of order-disorder transition in refractory high entropy alloys: A data-driven approach

Enhanced Hardness in High‐Entropy Carbides through Atomic Randomness

Designing Transformation-Induced Plasticity and Twinning-Induced Plasticity Cr-Co-Ni Medium Entropy Alloys: Theory and Experiment

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