Fast Slip Velocity in a High-Entropy Alloy

Rizzardi, Q.; Sparks, Gregory; Maaß, R.

doi:10.1007/s11837-018-2856-6

Cited by 17 publications

(20 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are now sufficient studies that have revealed that the strengthening of dislocation motion in HEAs is strongly dependent upon its susceptibility to display either short or long range ordering effects rather than simple lattice friction-induced hardening responses [43,44]. This was validated by a recent study by Robert Maaß and collaborators, wherein the peak dislocation velocities in FCC Al 0.3 CoCrFeNi and pure Au did not show much difference, indicating that dislocation motion was not significantly sluggish in single phase solid solution HEAs (Rizzardi et al [45]). Moreover, the contributions of interfacial-dependent strengthening and solute strengthening modes need to be appraised, as these could be critical in driving application-based future multiphase HEA alloy design.…”

Section: An Outlook To Heas: Structural Propertiesmentioning

confidence: 78%

High Entropy Alloys: Ready to Set Sail?

Basu

Hosson

2020

Metals

View full text Add to dashboard Cite

Over the past decade, high entropy alloys (HEAs) have transcended the frontiers of material development in terms of their unprecedented structural and functional properties compared to their counterpart conventional alloys. The possibility to explore a vast compositional space further renders this area of research extremely promising in the near future for discovering society-changing materials. The introduction of HEAs has also brought forth a paradigm shift in the existing knowledge about material design and development. It is in this regard that a fundamental understanding of the metal physics of these alloys is critical in propelling mechanism-based HEA design. The current paper highlights some of the critical viewpoints that need greater attention in the future with respect to designing mechanically and functionally advanced materials. In particular, the interplay of large compositional gradients and defect topologies in these alloys and their corresponding impact on overall mechanical response are highlighted. From the point of view of functional response, such chemistry vis-à-vis topology correlations are extended to novel class of nano-porous HEAs that beat thermal coarsening effects despite a high surface to volume ratio owing to retarded diffusion kinetics. Recommendations on material design with regards to their potential use in diverse applications such as energy storage, actuators, and as piezoelectrics are additionally considered.

show abstract

Section: An Outlook To Heas: Structural Propertiesmentioning

confidence: 78%

High Entropy Alloys: Ready to Set Sail?

Basu

Hosson

2020

Metals

View full text Add to dashboard Cite

show abstract

“…Such homogenization schemes are fundamentally based on Gaussian-like statistics with well-defined mean values and stand in stark contrast to a few selected bulk * robert.maass@bam.de deformation studies that report scale-free deformation [7][8][9]. The signature of scale-free and thus non-Gaussian dislocation activity has been revealed with acoustic-emission sensing on bulk hexagonal closest packed (hcp) crystals [10,11] and a plethora of recent small-scale deformation experiments across numerous material systems [12][13][14][15][16][17][18][19][20][21]. One of the dominant findings was that a lot of experimental data showed agreement with analytical statistical physics frameworks, notably a pinning-depinning model for avalanches near the depinning transition [22].…”

Section: Introductionmentioning

confidence: 99%

“…This approach is motivated by our desire to understand if certain parts of the event-size distribution are statistically favoring a particular slip morphology and therefore spatial localization. In the view of our earlier results demonstrating nontrivial and nonuniversal scaling exponents [12][13][14]25,27,33], it furthermore became of interest what statistical scaling particular types of slip morphologies, if they are definable, may have. These considerations emerged out of our observation that postmortem visualized slip patterns across different types of single crystals can be dramatically different while exhibiting statistical scaling that was practically identical.…”

Section: Introductionmentioning

confidence: 99%

“…This paper details uniaxial microcrystal compression experiments on a single crystalline high-entropy alloy (HEA) that are conducted inside a scanning electron microscope (SEM). The choice of an HEA was based on the high probability of sufficiently large slip events [13] such that slip lines could be resolved inside the SEM. Pausing the quasistatic straining after each detected slip event, images were acquired that subsequently could be analyzed with respect to their differences.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Microstructural signatures of dislocation avalanches in a high-entropy alloy

Rizzardi

Derlet

Maaß

2021

Phys. Rev. Materials

Self Cite

View full text Add to dashboard Cite

Here, we trace in situ the slip-line formation and morphological signature of dislocation avalanches in a highentropy alloy with the aim of revealing their microstructural degree of localization. Correlating the intermittent microplastic events with their corresponding slip-line patterns allows defining two main event types, one of which is linked to the formation of new slip lines, whereas the other one involves reactivation of already existing slip lines. The formation of new slip lines reveals statistically larger and faster avalanches. The opposite tendency is seen for avalanches involving reactivation of already existing slip lines. The combination of both these types of events represents the highest degree of spatial avalanche delocalization that spans the entire sample, forming a group of events that determine the truncation length scale of the truncated power-law scaling. These observations link the statistics of dislocation avalanches to a microstructural observable.

show abstract

“…Another fundamental and intriguing aspect that emanates from such experiments is that, in addition to the materialdependent response, there is a testing device-dependent effect on the measured slip velocities [18,22,23]. As previous studies show [19,[24][25][26], the most important variable is the externally applied deformation rate, suggesting that-within the data scatter-there is a fundamental relation between the onset of plastic instabilities and the prescribed speed of deformation.…”

mentioning

confidence: 98%

Avalanche statistics and the intermittent-to-smooth transition in microplasticity

Sparks

Cui

et al. 2019

Phys. Rev. Materials

Self Cite

View full text Add to dashboard Cite

Plastic flow at small scales is generally observed to be intermittent, whereas the stress-strain behavior of bulk crystals is mostly smooth. Here we find that when the external deformation rate of small-scale crystals approaches the speed of the crystallographic slip velocity, an intermittent-to-smooth transition of plastic flow is observed. By defining a rate-dependent intermittency parameter, this phenomenon can be captured with a power law covering 5.5 orders of magnitude for Au and Nb micron-sized single crystals with experiments and via simulations for Nb crystals. Our results indicate that the transition to smooth flow is driven by a gradual truncation of the underlying truncated power law that describes the intermittently evolving system. This is caused by a competition of internal and external rates, which aligns with the well-known transitions from serrated to nonserrated flow in metallic glasses or materials with dynamic strain aging.

show abstract

Fast Slip Velocity in a High-Entropy Alloy

Cited by 17 publications

References 36 publications

High Entropy Alloys: Ready to Set Sail?

High Entropy Alloys: Ready to Set Sail?

Microstructural signatures of dislocation avalanches in a high-entropy alloy

Avalanche statistics and the intermittent-to-smooth transition in microplasticity

Contact Info

Product

Resources

About