More Like this

1. Segregation Energy Spectra of Co in Aluminum Grain Boundaries that span the 5D space of Crystallographic Character

   https://doi.org/10.17632/rf3bt5f4hd  

   Serafin, Lydia; Cluff, Ethan; Hart, Gus; Homer, Eric (October 2024, Mendeley Data)

   This dataset provides segregation energy spectra information for cobalt solute in 7272 aluminum grain boundaries that span the 5D space of crystallographic character. The dataset and some of its characteristics are described in detail in https://doi.org/10.1016/j.actamat.2024.120448. The information about the segregation energy spectra are included in a CSV file. Each GB is identified by a computeID that is listed in the CSV file. The crystallographic character and selected properties for each GB, as well as its structure, are available in another dataset at https://doi.org/10.17632/4ykjz4ngwt, and which is described in an article at https://doi.org/10.1016/j.actamat.2022.118006. Note that the A README file provides a description of the columns of the CSV file. 

   more » « less
2. Atomistic and machine learning studies of solute segregation in metastable grain boundaries

   https://doi.org/10.1038/s41598-022-10566-5  

   Mahmood, Yasir; Alghalayini, Maher; Martinez, Enrique; Paredis, Christiaan J.; Abdeljawad, Fadi (December 2022, Scientific Reports)

   Abstract The interaction of alloying elements with grain boundaries (GBs) influences many phenomena, such as microstructural evolution and transport. While GB solute segregation has been the subject of active research in recent years, most studies focus on ground-state GB structures, i.e., lowest energy GBs. The impact of GB metastability on solute segregation remains poorly understood. Herein, we leverage atomistic simulations to generate metastable structures for a series of [001] and [110] symmetric tilt GBs in a model Al–Mg system and quantify Mg segregation to individual sites within these boundaries. Our results show large variations in the atomic Voronoi volume due to GB metastability, which are found to influence the segregation energy. The atomistic data are then used to train a Gaussian Process machine learning model, which provides a probabilistic description of the GB segregation energy in terms of the local atomic environment. In broad terms, our approach extends existing GB segregation models by accounting for variability due to GB metastability, where the segregation energy is treated as a distribution rather than a single-valued quantity. 

   more » « less
3. Stochastic model and kinetic Monte Carlo simulation of solute interactions with stationary and moving grain boundaries. II. Application to two-dimensional systems

   https://doi.org/https://doi.org/10.1103/PhysRevMaterials.7.063404  

   Mishin, Y. (June 2023, Physical Review Materials)

   In Part I of this work, we proposed a stochastic model describing solute interactions with stationary and moving grain boundaries (GBs) and applied it to planar GBs in 1D systems. The model reproduces nonlinear GB dynamics, solute saturation in the segregation atmosphere, and all basic features of the solute drag effect. Part II of this work extends the model to 2D GBs represented by solid-on-solid interfaces. The model predicts a GB roughening transition in stationary GBs and reversible dynamic roughening in moving GBs. The impacts of the GB roughening on GB migration mechanisms, GB mobility, and the solute drag are studied in detail. The threshold effect in GB dynamics is explained by the dynamic roughening transition, which is amplified in the presence of solute segregation. The simulation results are compared with the classical models by Cahn and Lücke-Stüwe and previous computer simulations. 

   more » « less
4. Tuning grain boundary cation segregation with oxygen deficiency and atomic structure in a perovskite compositionally complex oxide thin film

   https://doi.org/10.1063/5.0202249  

   Guo, Huiming; Vahidi, Hasti; Kang, Hyojoo; Shah, Soham; Xu, Mingjie; Aoki, Toshihiro; Rupert, Timothy J.; Luo, Jian; Gilliard-AbdulAziz, Kandis Leslie; Bowman, William J. (April 2024, Applied Physics Letters)

   Compositionally complex oxides (CCOs) are an emerging class of materials encompassing high entropy and entropy stabilized oxides. These promising advanced materials leverage tunable chemical bond structure, lattice distortion, and chemical disorder for unprecedented properties. Grain boundary (GB) and point defect segregation to GBs are relatively understudied in CCOs even though they can govern macroscopic material properties. For example, GB segregation can govern local chemical (dis)order and point defect distribution, playing a critical role in electrochemical reaction kinetics, and charge and mass transport in solid electrolytes. However, compared with conventional oxides, GBs in multi-cation CCO systems are expected to exhibit more complex segregation phenomena and, thus, prove more difficult to tune through GB design strategies. Here, GB segregation was studied in a model perovskite CCO LaFe0.7Ni0.1Co0.1Cu0.05Pd0.05O3−x textured thin film by (sub-)atomic-resolution scanning transmission electron microscopy imaging and spectroscopy. It is found that GB segregation is correlated with cation reducibility—predicted by an Ellingham diagram—as Pd and Cu segregate to GBs rich in oxygen vacancies (VO··). Furthermore, Pd and Cu segregation is highly sensitive to the concentration and spatial distribution of VO·· along the GB plane, as well as fluctuations in atomic structure and elastic strain induced by GB local disorder, such as dislocations. This work offers a perspective of controlling segregation concentration of CCO cations to GBs by tuning reducibility of CCO cations and oxygen deficiency, which is expected to guide GB design in CCOs. 

   more » « less
5. Size-dependent attraction of Cu solutes to clusters formed at Ag grain boundaries

   https://doi.org/10.1103/t7qb-g8n6  

   Nikitin, Pavel; Sansoz, Frederic (September 2025, Physical Review Materials)

   We report a size-dependent solute clustering mechanism at grain boundaries in a sputtered ultrafine-grained Ag-Cu alloy, where large Cu clusters form despite weak individual solute-solute interactions. X-ray diffraction confirms limited Cu solubility in the Ag matrix, while scanning transmission electron microscopy reveals Cu clustering at both ordinary GBs and GB junctions. Density functional theory calculations show that 12-atom Cu clusters are energetically preferred, while smaller three-atom clusters are significantly less stable. Additional calculations demonstrate a marked increase in solute-cluster attraction energy with cluster size. These findings point to a previously unrecognized pathway for grain-boundary solute clustering in immiscible systems, driven by collective solute-cluster interactions, with implications for segregation behavior and stability in nanocrystalline and ultrafine-grained alloys. 

   more » « less