Dynamic response of high-entropy alloys to ballistic impact

Tang, Yunqing; Li, D.Y.

doi:10.1126/sciadv.abp9096

Cited by 57 publications

(5 citation statements)

References 75 publications

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“…In recent years, MD simulations were widely utilized to study the mechanical properties and deformation mechanisms of the HEAs. The predicted results from these MD simulations [26][27][28][29][30][31][32] can not only agree well with the experimental data but also reveal the new deformation mechanisms at microscale that is difficult to obtain in experiments.…”

Section: Introductionsupporting

confidence: 73%

Atomistic evaluation of tension–compression asymmetry in nanoscale body-centered-cubic AlCrFeCoNi high-entropy alloy

Xing 邢,

Liu 刘

2024

Chinese Phys. B

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The tension and compression of face-centered-cubic high-entropy alloy (HEA) nanowires are significantly asymmetric, but the tension-compression asymmetry in nanoscale body-centered-cubic (BCC) HEAs is still unclear. In this study, the tension-compression asymmetry of the BCC AlCrFeCoNi HEA nanowire is investigated using molecular dynamics simulations. The results show a significant asymmetry in both the yield and flow stresses, with BCC HEA nanowire stronger under compression than under tension. The strength asymmetry originates from the completely different deformation mechanisms in tension and compression. In compression, atomic amorphization dominates plastic deformation and contributes to the strengthening, while in tension, deformation twinning prevails and weakens the HEA nanowire. The tension-compression asymmetry exhibits a clear trend of increasing with the increasing nanowire cross-sectional edge length and decreasing temperature. In particular, the compressive strengths along the [001] and [111] crystallographic orientations are stronger than the tensile counterparts, while the [110] crystallographic orientation shows the exactly opposite trend. The dependences of tension-compression asymmetry on the cross-sectional edge length, crystallographic orientation, and temperature are explained in terms of the deformation behavior of HEA nanowire as well as its variations caused by the change in these influential factors. These findings may deepen our understanding of the tension-compression asymmetry of the BCC HEA nanowires.

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Section: Introductionsupporting

confidence: 73%

Atomistic evaluation of tension–compression asymmetry in nanoscale body-centered-cubic AlCrFeCoNi high-entropy alloy

Xing 邢,

Liu 刘

2024

Chinese Phys. B

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“…As a result of their particularly high mechanical properties (hardness, ballistic impact, wear) [ 16 , 17 ] and good behavior in chemical environments, high-entropy alloys from the AlCoCrFeNi system have been among the most studied metallic materials in recent years [ 18 , 19 , 20 , 21 ]. The microstructures of alloys largely depend on the proportion of alloying elements.…”

Section: Introductionmentioning

confidence: 99%

Structural Parameters and Behavior in Simulated Body Fluid of High Entropy Alloy Thin Films

Craciun,

Laszlo,

Mirza-Rosca

et al. 2024

Materials

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The structure, composition and corrosion properties of thin films synthesized using the Pulsed Laser Deposition (PLD) technique starting from a three high entropy alloy (HEA) AlCoCrFeNix produced by vacuum arc remelting (VAR) method were investigated. The depositions were performed at room temperature on Si and mirror-like polished Ti substrates either under residual vacuum (low 10−7 mbar, films denoted HEA2, HEA6, and HEA10, which were grown from targets with Ni concentration molar ratio, x, equal to 0.4, 1.2, and 2.0, respectively) or under N2 (10−4 mbar, films denoted HEN2, HEN6, and HEN10 for the same Ni concentration molar ratios). The deposited films’ structures, investigated using Grazing Incidence X-ray Diffraction, showed the presence of face-centered cubic and body-centered cubic phases, while their surface morphology, investigated using scanning electron microscopy, exhibited a smooth surface with micrometer size droplets. The mass density and thickness were obtained from simulations of acquired X-ray reflectivity curves. The films’ elemental composition, estimated using the energy dispersion X-ray spectroscopy, was quite close to that of the targets used. X-ray Photoelectron Spectroscopy investigation showed that films deposited under a N2 atmosphere contained several percentages of N atoms in metallic nitride compounds. The electrochemical behavior of films under simulated body fluid (SBF) conditions was investigated by Open Circuit Potential (OCP) and Electrochemical Impedance Spectroscopy measurements. The measured OCP values increased over time, implying that a passive layer was formed on the surface of the films. It was observed that all films started to passivate in SBF solution, with the HEN6 film exhibiting the highest increase. The highest repassivation potential was exhibited by the same film, implying that it had the highest stability range of all analyzed films. Impedance measurements indicated high corrosion resistance values for HEA2, HEA6, and HEN6 samples. Much lower resistances were found for HEN10 and HEN2. Overall, HEN6 films exhibited the best corrosion behavior among the investigated films. It was noticed that for 24 h of immersion in SBF solution, this film was also a physical barrier to the corrosion process, not only a chemical one.

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“…However, despite this understanding of dynamic failure, the detailed microscopic mechanisms, particularly the linkage between local microstructure and the dynamic behavior of materials, remain unclear. Recent molecular dynamics (MD) simulations indicate that the local chemical fluctuation can markedly affect both dislocation activities ( 46 ) and the void dynamics in HEAs ( 47 ) and, hence, influence their impact resistance. Further understanding of the underlying material physics would certainly aid the design of impact-resistant materials, which has been an ongoing challenge for many applications including vehicle crash safety, penetration protection, and aerospace engineering.…”

Section: Introductionmentioning

confidence: 99%

Deformation and failure of the CrCoNi medium-entropy alloy subjected to extreme shock loading

et al. 2023

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The extraordinary work hardening ability and fracture toughness of the face-centered cubic (fcc) high-entropy alloys render them ideal candidates for many structural applications. Here, the deformation and failure mechanisms of an equiatomic CrCoNi medium-entropyalloy (MEA) were investigated by powerful laser-driven shock experiments. Multiscale characterization demonstrates that profuse planar defects including stacking faults, nanotwins, and hexagonal nanolamella were generated during shock compression, forming a three-dimensional network. During shock release, the MEA fractured by strong tensile deformation and numerous voids was observed in the vicinity of the fracture plane. High defect populations, nanorecrystallization, and amorphization were found adjacent to these areas of localized deformation. Molecular dynamics simulations corroborate the experimental results and suggest that deformation-induced defects formed before void nucleation govern the geometry of void growth and delay their coalescence. Our results indicate that the CrCoNi-based alloys are impact resistant, damage tolerant, and potentially suitable in applications under extreme conditions.

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Dynamic response of high-entropy alloys to ballistic impact

Cited by 57 publications

References 75 publications

Atomistic evaluation of tension–compression asymmetry in nanoscale body-centered-cubic AlCrFeCoNi high-entropy alloy

Atomistic evaluation of tension–compression asymmetry in nanoscale body-centered-cubic AlCrFeCoNi high-entropy alloy

Structural Parameters and Behavior in Simulated Body Fluid of High Entropy Alloy Thin Films

Deformation and failure of the CrCoNi medium-entropy alloy subjected to extreme shock loading

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