arXiv subjects

Ayobami Daramola

Publications and source records attributed to Ayobami Daramola.

4 recordsLinked to original sources

arXiv2026

Topological Signatures of Hardness and Structural Order in Network-Forming Materials

Understanding how the topology of network forming materials influences their physical properties remains a longstanding challenge. Here, we investigate the topology of experimentally compatible atomistic models of amorphous silica together with the crystalline polymorphs cristobalite and quartz. By comparing multiple atomistic models of amorphous silica that equally reproduce neutron-scattering data, we show that different microscopic descriptions can imply different topological interpretations of glass stability. To characterize the network beyond conventional geometric descriptors, we introduce the linking valence, which quantifies the average number of topological links per network loop. This topological descriptor separates silica into two distinct classes: the mechanically harder quartz exhibit values more than an order of magnitude larger than those of amorphous silica and cristobalite, despite their common tetrahedral building blocks. Spectral analysis of the loop-linking networks provides a complementary distinction, separating amorphous from crystalline phases and revealing differences in the long-range organization of topological constraints. These results establish topological linking as a new framework for connecting the structure and physical properties of network-forming materials.

cond-mat.mtrl-sci↗

arXiv2024

Predicting Thermal Stress and Failure Risk in Monoblock Divertors Using 2D Finite Difference Modelling and Gradient Boosting Regression for Fusion Energy Applications

This study presents a combined approach using a 2D finite difference method and Gradient Boosting Regressor (GBR) to analyze thermal stress and identify potential failure points in monoblock divertors made of tungsten, copper, and CuCrZr alloy. The model simulates temperature and heat flux distributions under typical fusion reactor conditions, highlighting regions of high thermal gradients and stress accumulation. These stress concentrations, particularly at the interfaces between materials, are key areas for potential failure, such as thermal fatigue and microcracking. Using the GBR model, a predictive maintenance framework is developed to assess failure risk based on thermal stress data, allowing for early intervention. This approach provides insights into the thermomechanical behavior of divertors, contributing to the design and maintenance of more resilient fusion reactor components.

physics.plasm-ph↗

arXiv2022

Atomistic Investigation of Elementary Dislocation Properties Influencing Mechanical Behaviour of $Cr_{15}Fe_{46}Mn_{17}Ni_{22}$ alloy and $Cr_{20}Fe_{70}Ni_{10}$ alloy

In this work, molecular dynamics (MD) simulations were used to investigate elementary dislocation properties in a Co-free high entropy (HEA) model alloy ($Cr_{15}Fe_{46}Mn_{17}Ni_{22}$ at. %) in comparison with a model alloy representative of Austenitic Stainless Steel (ASS) ($Cr_{20}Fe_{70}Ni_{10}$ at. %). Recently developed embedded-atom method (EAM) potentials were used to describe the atomic interactions in the alloys. Molecular Statics (MS) calculations were used to study the dislocation properties in terms of local stacking fault energy (SFE), dissociation distance while MD was used to investigate the dissociation distance under applied shear stress as a function of temperature and strain rate. It was shown that higher critical stress is required to move dislocations in the HEA alloy compared with the ASS model alloy. The theoretical investigation of simulation results of the dislocation mobility shows that a simple constitutive mobility law allows to predict dislocation velocity in both alloys over three orders of magnitude, covering the phonon drag regime and the thermally activated regime induced by dislocation unpinning from local hard configurations.

physics.atm-clus↗

arXiv2022

Development of a Plasticity-oriented Interatomic Potential for CrFeMnNi High Entropy Alloys

An interatomic potential (termed EAM-21) has been developed with the embedded atomic method (EAM) for CrFeMnNi quaternary HEAs. This potential is based on a previously developed potential for CrFeNi ternary alloys. The parameters to develop the potential were determined by fitting to experimental values, density functional theory (DFT) and thermodynamic calculations, to reproduce the main crystal characteristics, namely: the stability of the fcc phase, elastic constants, and stacking fault energy. Its applicability for the study of plastic deformation mechanisms was checked by calculations of behaviour of a $< 110>\left \{1111 \right \}$ edge dislocation in equiatomic quaternary CrFeMnNi alloy, as well as its less-complex subsystems (ternaries, binaries, and pure metals). The calculations were performed in the domain of temperatures between 0 and 900 K; smooth and stable glide of an edge dislocation and fcc phase stability in this temperature range was confirmed. This study demonstrates the suitability of the EAM-21 potential for the analysis of plasticity mechanisms and mechanical properties of CrFeMnNi HEAs.

cond-mat.mtrl-sci↗