Is this you? As a journalist, you can create a free Muck Rack account to customize your profile, list your contact preferences, and upload a portfolio of your best work.
Claim your profile
Articles by Mark Asta
Competing mechanisms toughen bcc binary and medium-entropy alloys at 20 K
Abstract Plastic deformation in body-centred cubic (bcc) metals and alloys is conventionally mediated by screw dislocations. Their temperature-sensitive motion is attributed to a steep rise in strength with decreasing temperature that constricts plastic zones at crack tips, leading to a ductile-to-brittle transition1.
SuperSalt: equivariant neural network force fields for multicomponent molten salts system - Nature Communications
Abstract Molten salts are crucial for clean energy applications, yet exploring their thermophysical properties across diverse chemical space remains challenging. We present the development of a machine learning interatomic potential (MLIP) called SuperSalt, which targets 11-cation chloride melts and captures the essential physics of molten salts with near-DFT accuracy.
Memsensing by surface ion migration within Debye length - Nature Materials
Abstract Integration between electronics and biology is often facilitated by iontronics, where ion migration in aqueous media governs sensing and memory. However, the Debye screening effect limits electric fields to the Debye length, the distance over which mobile ions screen electrostatic interactions, necessitating external voltages that constrain the operation speed and device design.
Accelerating phase field simulations through a hybrid adaptive Fourier neural operator with U-net backbone - npj Computational Materials
Abstract Prolonged contact between a corrosive liquid and metal alloys can cause progressive dealloying. For one such process as liquid-metal dealloying (LMD), phase field models have been developed to understand the mechanisms leading to complex morphologies. However, the LMD governing equations in these models often involve coupled non-linear partial differential equations (PDE), which are challenging to solve numerically.
Grand canonically optimized grain boundary phases in hexagonal close-packed titanium - Nature Communications
Abstract Grain boundaries (GBs) profoundly influence the properties and performance of materials, emphasizing the importance of understanding the GB structure and phase behavior. As recent computational studies have demonstrated the existence of multiple GB phases associated with varying the atomic density at the interface, we introduce a validated, open-source GRand canonical Interface Predictor (GRIP) tool that automates high-throughput, grand canonical optimization of GB structures.
Rejuvenation as the origin of planar defects in the CrCoNi medium entropy alloy - Nature Communications
Abstract High or medium- entropy alloys (HEAs/MEAs) are multi-principal element alloys with equal atomic elemental composition, some of which have shown record-breaking mechanical performance. However, the link between short-range order (SRO) and the exceptional mechanical properties of these alloys has remained elusive.
Phys. Rev. Materials 8, 013608 (2024) - Elucidating the roles of chemistry, compositional complexity, and short-range order in the dislocation energetics of body-centered-cubic concentrated solid solutions
Dislocation-mediated deformation mechanisms in body-centered-cubic solid solutions are expected to be influenced by spatial fluctuations in screw dislocation core energies. In refractory high-entropy alloys, the formation of chemical short-range order has been demonstrated to decrease the heterogeneity of this energy landscape, narrowing the distribution of dislocation core energies.
Grain boundary effects in high-temperature liquid-metal dealloying: a multi-phase field study - npj Computational Materials
Abstract A multi-phase field model is employed to study the microstructural evolution of an alloy undergoing liquid dealloying, specifically considering the role of grain boundaries. A semi-implicit time-stepping algorithm using spectral methods is implemented, which enables simulating large 2D and 3D domains over long time scales while still maintaining a realistic interfacial thickness.
Theory-guided design of high-entropy alloys with enhanced strength-ductility synergy - Nature Communications
Abstract Metallic alloys have played essential roles in human civilization due to their balanced strength and ductility. Metastable phases and twins have been introduced to overcome the strength-ductility tradeoff in face-centered cubic (FCC) high-entropy alloys (HEAs). However, there is still a lack of quantifiable mechanisms to predict good combinations of the two mechanical properties.
Simulating short-range order in compositionally complex materials - Nature Computational Science
The problem inherent to sampling millions of configurations with DFT is its low computational efficiency. To address this issue, energies and forces derived from quantum mechanics must be obtained from a simpler mathematical format for the interatomic interactions between atoms, but finding accurate interactions that best mimic the multi-body relations between real atoms is not straightforward.
One dimensional wormhole corrosion in metals - Nature Communications
Abstract Corrosion is a ubiquitous failure mode of materials. Often, the progression of localized corrosion is accompanied by the evolution of porosity in materials previously reported to be either three-dimensional or two-dimensional. However, using new tools and analysis techniques, we have realized that a more localized form of corrosion, which we call 1D wormhole corrosion, has previously been miscategorized in some situations.
Theoretical prediction of high melting temperature for a Mo-Ru-Ta-W HCP multiprincipal element alloy
Abstract While rhenium is an ideal material for rapid thermal cycling applications under high temperatures, such as rocket engine nozzles, its high cost limits its widespread use and prompts an exploration of viable cost-effective substitutes. In prior work, we identified a promising pool of candidate substitute alloys consisting of Mo, Ru, Ta, and W.
Defect reconfiguration in a Ti-Al alloy via electroplasticity
Abstract It has been known for decades that the application of pulsed direct current can significantly enhance the formability of metals. However, the detailed mechanisms of this effect have been difficult to separate from simple Joule heating. Here, we study the electroplastic deformation of Ti–Al (7 at.% Al), an alloy that is uniquely suited for uncoupling this behaviour because, contrary to most metals, it has inherently lower ductility at higher temperature.
Short-range order and its impact on the CrCoNi medium-entropy alloy
Abstract Traditional metallic alloys are mixtures of elements in which the atoms of minority species tend to be distributed randomly if they are below their solubility limit, or to form secondary phases if they are above it. The concept of multiple-principal-element alloys has recently expanded this view, as these materials are single-phase solid solutions of generally equiatomic mixtures of metallic elements.
NMR Crystallography: Evaluation of Hydrogen Positions in Hydromagnesite by 13C{1H} REDOR Solid‐State NMR and Density Functional Theory Calculation of Chemical Shielding Tensors - Cui - - Angewandte Chemie International Edition - Wiley Online Library
The full text of this article hosted at iucr.org is unavailable due to technical difficulties. Communication NMR Crystallography: Evaluation of Hydrogen Positions in Hydromagnesite by 13C{1H} REDOR Solid‐State NMR and Density Functional Theory Calculation of Chemical Shielding Tensors Prof. Sophia E.
NMR Crystallography: Evaluation of Hydrogen Positions in Hydromagnesite by ¹³C{¹H} REDOR Solid‐State NMR and Density Functional Theory Calculation of Chemical Shielding Tensors - Cui - - Angewandte Chemie International Edition - Wiley Online Library
The full text of this article hosted at iucr.org is unavailable due to technical difficulties.
Quantum effects on dislocation motion from ring-polymer molecular dynamics
As a baseline for subsequent comparison, first we compute the Peierls stress using fully classical simulations. Defined as the minimal stress required to make a dislocation move in the limit of zero temperature, Peierls stress can be computed in a static simulation in which stress or strain is increased in increments, each increment followed by a full relaxation of atom positions. The Peierls stress is taken to be just one increment below the stress at which the dislocation begins to move.
Spatial correlation of elastic heterogeneity tunes the deformation behavior of metallic glasses
The nanoscale elastic heterogeneity is identified using MD simulations of the model Cu Zr MGs, as shown in Fig. 1a, b. The local shear moduli for two model MGs with different cooling rates (109 K/s and 1011 K/s) are computed by a fluctuation method.22,23,24 At 300 K, the shear moduli in both models exhibit the Gaussian distribution. The MD simulations reveal that the distribution of the local shear moduli is sensitive to the thermal history of the model MG. Fig.
Show More
loading
Actions
Is this you?
As a journalist, you can create a free Muck Rack account to customize your profile, list your contact preferences, and upload a portfolio of your best work.Get in touch with Mark
Contact Mark, search articles and posts on X, monitor coverage, and track replies from one place.
Learn more about Muck Rack