Scholarly Works, Materials Science and Engineering (MSE)

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Multi-stage precipitation modeling for AA 7050 hole repairs in additive friction stir deposition
Feng, Bill; Rajanna, Manoj R.; Lua, Jim; Hahn, Greg; Knight, Kendall; Murray, Gabriel; Timmons, Alan; Phan, Nam (AIP Publishing, 2024-10-28)
A multi-stage precipitation model is formulated to predict the microstructural evolution and explain the high performance of additive friction stir deposited aluminum alloy 7050 (AA 7050) for hole repair. The first stage is the heating process due to the high-temperature thermomechanical process of the stir. In this process, small eta precipitates dissolve as they lose their stability with increasing temperature, and this causes the volume fraction of eta precipitates to decrease and the concentration of Mg and Zn in the matrix to increase. The second stage is the cooling process at the end of the repair where material feeding ends and the tool is lifted away. Heterogeneous nucleation of eta precipitates may occur and as the temperature cools below 250 degrees C, Guinier-Preston (GP) zones start to form. The final stage is the natural aging process, where the eta ' precipitate starts to grow. The volume fraction and precipitate radius are predicted for each type of precipitate. Furthermore, the fine eta ' precipitates and GP zones with a decent volume fraction improve the material strength and fatigue life. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license
Order evolution from a high-entropy matrix: Understanding and predicting paths to low-temperature equilibrium
Almishal, Saeed S. I.; Miao, Leixin; Tan, Yueze; Kotsonis, George N.; Sivak, Jacob T.; Alem, Nasim; Chen, Long-Qing; Crespi, Vincent H.; Dabo, Ismaila; Rost, Christina M.; Sinnott, Susan B.; Maria, Jon-Paul (Wiley, 2025-02-01)
Interest in high-entropy inorganic compounds originates from their ability to stabilize cations and anions in local environments that rarely occur at standard temperature and pressure. This leads to new crystalline phases in many-cation formulations with structures and properties that depart from conventional trends. The highest-entropy homogeneous and random solid solution is a parent structure from which a continuum of lower-entropy offspring can originate by adopting chemical and/or structural order. This report demonstrates how synthesis conditions, thermal history, and elastic and chemical boundary conditions conspire to regulate this process in Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O, during which coherent CuO nanotweeds and spinel nanocuboids evolve. We do so by combining structured synthesis routes, atomic-resolution microscopy and spectroscopy, density functional theory, and a phase field modeling framework that accurately predicts the emergent structure and local chemistry. This establishes a framework to appreciate, understand, and predict the macrostate spectrum available to a high-entropy system that is critical to rationalizing property engineering opportunities.
Self-Healing and Stretchable Molecular Ferroelectrics with High Expandability
Wang, Zhongxuan; Yang, Haochen; Zhu, Long; Wang, Qian; Quan, Lina; Chen, Po-Yen; Ren, Shenqiang (Wiley-V C H Verlag, 2025-03-01)
The interplay between crystal ordering and stretchability is frequently encountered in contemporary materials science, particularly in the case of ferroelectrics. The inherent dilemma arises when these materials need to withstand repetitive mechanical deformations or stretching without sacrificing their crystal integrity, all while retaining their remarkable ferroelectric properties and even exhibiting self-healing capabilities. This complexity further presents a significant challenge in the design and engineering of mechanically rigid molecular ferroelectric crystals, particularly for applications where both precise crystalline structure and mechanical adaptability are crucial. In this study, the humidity-controlled expansion and contraction, dissolution, and recrystallization of a self-assembled molecular ferroelectric-in-hydrogel framework are reported. Self-healing ferroelectric-in-hydrogel networks exhibit a recyclable humidity-tailored ionic conductivity from 2.86 x 10-6 to 1.36 x 10-5 S cm-1, facilitating the stretchable piezoelectric sensing. Additionally, the dynamic bond reforming interactions are observed, leading to the tailoring of Young's modulus from 452 to 170 MPa, maintaining ferroelectricity under a strain of 20% with a piezoelectric coefficient of 15.7 pC N-1. Upon lattice contraction, the molecular contacts undergo reforming, leading to the restoration of stretchable ferroelectrics/piezoelectrics and paving the way for stretchable bioelectronics for full-body motion monitoring. The capabilities highlighted here open avenues for stretchable and self-healing ferroelectric-in-hydrogel bioelectronic technologies.
Scalable Accelerated Materials Discovery of Sustainable Polysaccharide-Based Hydrogels by Autonomous Experimentation and Collaborative Learning
Liu, Yang; Yue, Xubo; Zhang, Junru; Zhai, Zhenghao; Moammeri, Ali; Edgar, Kevin J.; Berahas, Albert S.; Al Kontar, Raed; Johnson, Blake N. (American Chemical Society, 2024-12-11)
While some materials can be discovered and engineered using standalone self-driving workflows, coordinating multiple stakeholders and workflows toward a common goal could advance autonomous experimentation (AE) for accelerated materials discovery (AMD). Here, we describe a scalable AMD paradigm based on AE and "collaborative learning". Collaborative learning using a novel consensus Bayesian optimization (BO) model enabled the rapid discovery of mechanically optimized composite polysaccharide hydrogels. The collaborative workflow outperformed a non-collaborating AMD workflow scaled by independent learning based on the trend of mechanical property evolution over eight experimental iterations, corresponding to a budget limit. After five iterations, four collaborating clients obtained notable material performance (i.e., composition discovery). Collaborative learning by consensus BO can enable scaling and performance optimization for a range of self-driving materials research workflows driven by optimally cooperating humans and machines that share a material design objective.
Copper Oxidation-Induced Nanoscale Deformation of Electromechanical, Laminate Polymer/Graphene Thin Films during Thermal Annealing: Implications for Flexible, Transparent, and Conductive Electrodes
Croft, Zacary L.; Valenzuela, Oscar; Thompson, Connor; Whitfield, Brendan; Betzko, Garrett; Liu, Guoliang (American Chemical Society, 2024-12-12)
The transfer of large-area, continuous, chemical vapor deposition (CVD)-grown graphene without introducing defects remains a challenge for fabricating graphene-based electronics. Polymer thin films are commonly used as supports for transferring graphene, but they typically require thermal annealing before transfer. However, little work has been done to thoroughly investigate how thermal annealing affects the polymer/graphene thin film when directly annealed on the growth substrate. In this work, we demonstrate that under improper annealing conditions, thermal annealing of poly(ether imide)/single-layer graphene (PEI/SLG) thin films on Cu causes detrimental nanoscale structural deformations, which permanently degrade the mechanical properties. Furthermore, we elucidate the mechanisms of PEI/SLG deformation during thermal annealing and find that permanent deformations and cracking are caused by Cu substrate oxidation. This study provides an understanding of annealing-induced deformation in polymer/graphene thin films. We anticipate that this knowledge will be useful for further developing defect-free, graphene-based thin film electronics.
Magnetostrictive Behavior of Metglas® 2605SC and Acoustic Sensing Optical Fiber for Distributed Static Magnetic Field Detection
Dejneka, Zach; Homa, Daniel; Theis, Logan; Wang, Anbo; Pickrell, Gary (MDPI, 2025-09-12)
Fiber optic technologies have strong potential to augment and improve existing areas of sensor performance across many applications. Magnetic sensing, in particular, has attracted significant interest in structural health monitoring and ferromagnetic object detection. However, current technologies such as fluxgate magnetometers and inspection gauges rely on measuring magnetic fields as single-point sensors. By using fiber optic distributed strain sensors in tandem with magnetically biased magnetostrictive material, static and dynamic magnetic fields can be detected across long lengths of sensing fiber. This paper investigates the relationship between Fiber Bragg Grating (FBG)-based strain sensors and the magnetostrictive alloy Metglas^® 2605SC for the distributed detection of static fields for use in a compact cable design. Sentek Instrument’s picoDAS system is used to interrogate the FBG based sensors coupled with Metglas^® that is biased with an alternating sinusoidal magnetic field. The sensing system is then exposed to varied external static magnetic field strengths, and the resultant strain responses are analyzed. A minimum magnetic field strength on the order of 300 nT was able to be resolved and a variety of sensing configurations and conditions were also tested. The sensing system is compact and can be easily cabled as both FBGs and Metglas^® are commercialized and readily acquired. In combination with the robust and distributed nature of fiber sensors, this demonstrates strong promise for new means of magnetic characterization.
Optimizing Thermomechanical Processing for Producing Bulk Fine-Grained Aluminum Alloy with Thermal Stability
Punyafu, Jesada; Domrong, Chonlada; Patakham, Ussadawut; Murayama, Mitsuhiro; Banjongprasert, Chaiyasit (MDPI, 2025-09-05)
This study investigates the thermal stability of fine-grained structures achieved through different severe plastic deformation (SPD) and heat treatment paths. Bulk fine-grained Al-0.1Sc-0.1Zr (wt%) alloy was produced via equal channel angular pressing (ECAP) using routes Bc or C, with aging before or after the ECAP. Electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM) analyses demonstrate excellent thermal stability of all four specimens. They maintain mean grain sizes below 5 μm after a 10 h thermal test at 450 °C, attributed to the presence of nano Al₃(Sc,Zr) precipitates within the microstructures. Route Bc in the ECAP method forms more stable high-angle grain boundaries (HAGBs) than route C. Whether aging occurs before or after the ECAP, similar microstructural changes are observed after thermal testing, allowing fine-tuning of the microstructure depending on the application or subsequent processes.
Thermodynamics of calcium binding to heparin: Implications of solvation and water structuring for polysaccharide biofunctions
Knight, Brenna M.; Gallagher, Connor M. B.; Schulz, Michael D.; Edgar, Kevin J.; McNaul, Caylyn D.; McCutchin, Christina A.; Dove, Patricia M. (National Academy of Sciences, 2025-08-26)
Heparin sulfates are found in all animal tissues and have essential roles in living systems. This family of biomacromolecules modulates binding to calcium ions (Ca²⁺) in low free energy reactions that influence biochemical processes from cell signaling and anticoagulant efficacy to biomineralization. Despite their ubiquity, the thermodynamic basis for how heparans and similarly functionalized biomolecules regulate Ca²⁺ interactions is not yet established. Using heparosan (Control) and heparins with different positions of sulfate groups, we quantify how SO₃⁻ and COO⁻ content and SO₃⁻ position modulate Ca²⁺ binding by isothermal titration calorimetry. The free energy of all heparin-Ca²⁺ interactions (ΔGrxn) is dominated by entropic contributions due to favorable water release from polar, hydrophilic groups. Heparin with both sulfate esters (O-SO₃⁻) and sulfamides (N-SO₃⁻) has the strongest binding to Ca²⁺ compared to heparosan and to heparin with only O-SO₃⁻ groups (~3X). By linking Ca²⁺ binding thermodynamics to measurements of the interfacial energy for calcite (CaCO₃) crystallization onto polysaccharides, we show molecule-specific differences in nucleation rate can be explained by differences in water structuring during Ca²⁺ interactions. A large entropic term (-TΔSrxn) upon Ca²⁺–polysaccharide binding correlates with high interfacial energy to CaCO₃ nucleation. Combining our measurements with literature values indicates many Ca²⁺–polysaccharide interactions have a shared thermodynamic signature. The resulting enthalpy–entropy compensation relationship suggests these interactions are generally dominated by water restructuring involving few conformational changes, distinct from Ca²⁺–protein binding. Our findings quantify the thermodynamic origins of heparin-specific interactions with Ca²⁺ and demonstrate the contributions of solvation and functional group position during biomacromolecule-mediated ion regulation.
Self-Propelled Ice on Herringbones
Tapocik, Jack T.; Lolla, Venkata Yashasvi; Propst, Sarah E.; Nath, Saurabh; Boreyko, Jonathan B. (American Chemical Society, 2025-08-14)
In the Leidenfrost regime, droplets or sublimating solids can ratchet across asymmetric surface structures by viscous entrainment with the underlying vapor flow. As an extension to these liquid−vapor or solid−vapor ratchets, here, we investigate the solid−liquid self-propulsion of melting ice disks. On hydrophilic herringbones, ice disks self-propel due to the unidirectional flow of viscous meltwater. This is a more viscous analog to Leidenfrost ratchets, except now a brief start-up time is needed for the underlying channels to get filled. When the herringbone is superhydrophobic using conformal nanostructures, the ice disk partially adheres to the ridge tops such that viscous entrainment cannot induce motion. Instead, after a much longer start-up time, the ice disk suddenly dislodges and slingshots across the surface by virtue of a mismatch in Laplace pressure of the meltwater on either end of the disk.
Understanding Polysiloxane Polymer to Amorphous SiOC Conversion During Pyrolysis Through ReaxFF Simulation
Lu, Kathy; Chaney, Harrison (MDPI, 2025-03-22)
A significant challenge during the polymer-to-ceramic pyrolysis conversion is to understand the polymer-to-ceramic atomic evolution and correlate the composition changes with the precursor molecular structures, pyrolysis conditions, and resulting ceramic characteristics. In this study, a Reactive Force Field (ReaxFF) simulation approach has been used to simulate silicon oxycarbide (SiOC) ceramic formation from four different polysiloxane precursors. For the first time, we show atomically that pyrolysis time and temperature proportionally impact the new Si-O rich and C rich cluster sizes as well as the composition separation of Si-O from C. Polymer side groups have a more complex effect on the Si-O and C cluster separation and growth, with ethyl group leading to the most Si-O cluster separation and phenyl group leading to the most C cluster separation. We also demonstrate never-before correlations of gas release with polymer molecular structures and functional groups. CH₄, C₂H₆, C₂H₄, and H₂ are preferentially released from the pyrolyzing systems. The sequence is determined by the polymer molecular structures. This work is the first to atomically illustrate the innate correlations between the polymer precursors and pyrolyzed ceramics.
Investigating the effect of heterogeneities across the electrode|multiphase polymer electrolyte interfaces in high-potential lithium batteries
Min, Jungki; Bak, Seong-Min; Zhang, Yuxin; Yuan, Mingyu; Pietra, Nicholas F.; Russell, Joshua A.; Deng, Zhifei; Xia, Dawei; Tao, Lei; Du, Yonghua; Xiong, Hui; Li, Ling; Madsen, Louis A.; Lin, Feng (Nature Portfolio, 2025-04-01)
Polymer electrolytes hold great promise for safe and high-energy batteries comprising solid or semi-solid electrolytes. Multiphase polymer electrolytes, consisting of mobile and rigid phases, exhibit fast ion conduction and desired mechanical properties. However, fundamental challenges exist in understanding and regulating interactions at the electrode|electrolyte interface, especially when using high-potential layered oxide active materials at the positive electrode. Here we demonstrate that depletion of the mobile conductive phase at the interface contributes to battery performance degradation. Molecular ionic composite electrolytes, composed of a rigid-rod ionic polymer with nanometric mobile cations and anions, serve as a multiphase platform to investigate the evolution of ion conductive domains at the interface. Chemical and structural characterizations enable the visualization of concentration heterogeneity and spatially resolve the interfacial chemical states over a statistically significant field of view for buried interfaces. We report that concentration and chemical heterogeneities prevail at electrode|electrolyte interfaces, leading to phase separation in polymer electrolytes. Understanding the hidden roles of interfacial chemomechanics in polymer electrolytes enables us to design an interphase tailoring strategy based on electrolyte additives to mitigate the interfacial heterogeneity and improve battery performance.
Perspective on descriptors of mechanical behaviour of cubic transition-metal carbides and nitrides
Kindlund, Hanna; Ciobanu, Theodora; Kodambaka, Suneel; Ciobanu, Cristian V. (Taylor & Francis, 2024-05-31)
Cubic rocksalt structured transition-metal carbides, nitrides (TMC/Ns), and related alloys, are attractive for a wide variety of applications, notably as hard, wear-resistant materials. To-date, valence electron concentration (VEC) is used as a good indicator of stability and mechanical properties of these refractory compounds. In this perspective, we argue for the need of electronic descriptors beyond VEC to explain and predict the mechanical behaviour of the cubic TMC/Ns. As such, we point out that descriptors that highlight differences between constituents, along with semi-empirical models of mechanical properties, have been underused. Additionally, it appears promising to partition VEC into contribution to ionic, covalent, and metallic bonds and we suggest that such partition could provide more insights into predicting mechanical properties in the future.
Differential thermal analysis of the crystallization kinetics in perlite-based nanocrystalline glass-ceramics
Grigoryan, Lyova; Petrosyan, Petik; Asryan, Levon V.; Knyazyan, Nikolay; Petrosyan, Stepan (Institute of Rock Structure and Mechanics, AS CR, 2024-09-01)
A glass-ceramic material containing nanosized crystallites is synthesized based on the natural volcanic material perlite. Using the differential thermal analysis (DTA) method, the effect of Na2SiF6 (a crystallization catalyst from the fluoride group) on the glass crystallization properties is studied. The characteristic glass-transition temperature Tg, peak crystallization temperature Tp, as well as the crystallization activation energy (Ec) and Avrami index (n) are determined in terms of the catalyst content in the initial composition. A decrease in the nucleation agent content is shown to increase Tg, Tp, and Ec. The effect of the crystallization catalyst content on the crystallization mechanism and glass mechanical properties is discussed.
Lasers with double asymmetric barrier layers: Direct versus indirect capture of carriers into the lasing ground state in quantum dots
Hammack, Cody; Asryan, Levon V. (Wiley, 2024-12-19)
Static and dynamic characteristics of a quantum dot (QD) laser with double asymmetric barrier layers – an advanced type of semiconductor laser – are studied. Both direct and indirect capture of carriers into the lasing ground state in QDs is considered. The intradot relaxation of carriers, which controls the laser characteristics in the case of only indirect capture, is shown to not be a significant factor in the case of both direct and indirect capture. In the latter case, both the output optical power and modulation bandwidth are considerably increased.
Reversible Ferroelectric Polarization Modulation of Chiral Molecular Ferroelectrics by Circularly Polarized Light
Wang, Zhongxuan; Wang, Qian; Quan, Lina; Ren, Shenqiang (Wiley, 2025-01-21)
The optical modulation of ferroelectric polarization constitutes a transformative, non-contact strategy for the precise manipulation of ferroelectric properties, heralding advancements in optically stimulated ferroelectric devices. Despite its potential, progress in this domain is constrained by material limitations and the intricate nature of the underlying mechanisms. Recent studies have achieved efficient regulation of ferroelectric polarization and thermal conductivity in chiral ferroelectric thin films through the application of left- and right-handed circularly polarized light (LCP and RCP). Differential absorption of circularly polarized light (CPL) induces nonequilibrium carrier dynamics, generating distinctive interfacial electrostatic fields that enable precise control of ultrathin ferroelectric films. For (R)-BINOL−DIPASi and (S)-BINOL−DIPASi (C26H26O2Si), polarization changes surpass 23%, exhibiting opposite response under LCP and RCP excitation. In R chiral films, remnant polarization decreases from 1.05 µC cm−2 under LCP to 0.85 µC cm−2 under RCP, whereas in S chiral films, polarization increases from 0.85 µC cm−2 under LCP to 0.98 µC cm−2 under RCP. This reversible modulation facilitates reliable switching between ON and OFF states, presenting the potential of chiral ferroelectric materials for flexible, high-speed integrated photonic sensor technologies.
Magnet-in-ferroelectric crystals exhibiting photomultiferroicity
Wang, Zhongxuan; Wang, Qian; Gong, Weiyi; Chen, Amy; Islam, Abdullah; Quan, Lina; Woehl, Taylor J.; Yan, Qimin; Ren, Shenqiang (National Academy of Sciences, 2024-04-16)
Growing crystallographically incommensurate and dissimilar organic materials is fundamentally intriguing but challenging for the prominent cross-correlation phenomenon enabling unique magnetic, electronic, and optical functionalities. Here, we report the growth of molecular layered magnet-in-ferroelectric crystals, demonstrating photo-manipulation of interfacial ferroic coupling. The heterocrystals exhibit striking photomagnetization and magnetoelectricity, resulting in photomultiferroic coupling and complete change of their color while inheriting ferroelectricity and magnetism from the parent phases. Under a light illumination, ferromagnetic resonance shifts of 910 Oe are observed in heterocrystals while showing a magnetization change of 0.015 emu/g. In addition, a noticeable magnetization change (8% of magnetization at a 1,000 Oe external field) in the vicinity of ferro-to-paraelectric transition is observed. The mechanistic electric-field-dependent studies suggest the photoinduced ferroelectric field effect responsible for the tailoring of photo-piezo-magnetism. The crystallographic analyses further evidence the lattice coupling of a magnet-in-ferroelectric heterocrystal system.
Large exchange-driven intrinsic circular dichroism of a chiral 2D hybrid perovskite
Li, Shunran; Xu, Xian; Kocoj, Conrad A.; Zhou, Chenyu; Li, Yanyan; Chen, Du; Bennett, Joseph A.; Liu, Sunhao; Quan, Lina; Sarker, Suchismita; Liu, Mingzhao; Qiu, Diana Y.; Guo, Peijun (Nature Portfolio, 2024-03-22)
In two-dimensional chiral metal-halide perovskites, chiral organic spacers endow structural and optical chirality to the metal-halide sublattice, enabling exquisite control of light, charge, and electron spin. The chiroptical properties of metal-halide perovskites have been measured by transmissive circular dichroism spectroscopy, which necessitates thin-film samples. Here, by developing a reflection-based approach, we characterize the intrinsic, circular polarization-dependent complex refractive index for a prototypical two-dimensional chiral lead-bromide perovskite and report large circular dichroism for single crystals. Comparison with ab initio theory reveals the large circular dichroism arises from the inorganic sublattice rather than the chiral ligand and is an excitonic phenomenon driven by electron-hole exchange interactions, which breaks the degeneracy of transitions between Rashba-Dresselhaus-split bands, resulting in a Cotton effect. Our study suggests that previous data for spin-coated films largely underestimate the optical chirality and provides quantitative insights into the intrinsic optical properties of chiral perovskites for chiroptical and spintronic applications.
Acoustic Sensing Fiber Coupled with Highly Magnetostrictive Ribbon for Small-Scale Magnetic-Field Detection
Dejneka, Zach; Homa, Daniel; Theis, Logan; Wang, Anbo; Pickrell, Gary (MDPI, 2025-01-30)
Fiber-optic sensing has shown promising development for use in detecting magnetic fields for downhole and biomedical applications. Coupling existing fiber-based strain sensors with highly magnetostrictive materials allows for a new method of magnetic characterization capable of distributed and high-sensitivity field measurements. This study investigates the strain response of the highly magnetostrictive alloys Metglas^® 2605SC and Vitrovac^® 7600 T70 using Fiber Bragg Grating (FBG) acoustic sensors and an applied AC magnetic field. Sentek Instrument’s picoDAS interrogated the distributed FBG sensors set atop a ribbon of magnetostrictive material, and the corresponding strain response transferred to the fiber was analyzed. Using the Vitrovac^® ribbon, a minimal detectable field amplitude of 60 nT was achieved. Using Metglas^®, an even better sensitivity was demonstrated, where detected field amplitudes as low as 3 nT were measured via the strain response imparted to the FBG sensor. Distributed FBG sensors are readily available commercially, easily integrated into existing interrogation systems, and require no bonding to the magnetostrictive material for field detection. The simple sensor configuration with nanotesla-level sensitivity lends itself as a promising means of magnetic characterization and demonstrates the potential of fiber-optic acoustic sensors for distributed measurements.
Spinel oxide enables high-temperature self-lubrication in superalloys
Zhang, Zhengyu; Hershkovitz, Eitan; An, Qi; Liu, Liping; Wang, Xiaoqing; Deng, Zhifei; Baucom, Garrett; Wang, Wenbo; Zhao, Jing; Xin, Ziming; Moore, Lowell; Yi, Yao; Islam, Md Rezwan Ul; Chen, Xin; Cui, Bai; Li, Ling; Xin, Hongliang; Li, Lin; Kim, Honggyu; Cai, Wenjun (Nature Research, 2024-11-20)
The ability to lubricate and resist wear at temperatures above 600 °C in an oxidative environment remains a significant challenge for metals due to their high-temperature softening, oxidation, and rapid degradation of traditional solid lubricants. Herein, we demonstrate that high-temperature lubricity can be achieved with coefficients of friction (COF) as low as 0.10-0.32 at 600- 900 °C by tailoring surface oxidation in additively-manufactured Inconel superalloy. By integrating high-temperature tribological testing, advanced materials characterization, and computations, we show that the formation of spinel-based oxide layers on superalloy promotes sustained self-lubrication due to their lower shear strength and more negative formation and cohesive energy compared to other surface oxides. A reversible phase transformation between the cubic and tetragonal/monoclinic spinel was driven by stress and temperature during high temperature wear. To span Ni- and Cr-based ternary oxide compositional spaces for which little high-temperature COF data exist, we develop a computational design method to predict the lubricity of oxides, incorporating thermodynamics and density functional theory computations. Our finding demonstrates that spinel oxide can exhibit low COF values at temperatures much higher than conventional solid lubricants with 2D layered or Magnéli structures, suggesting a promising design strategy for selflubricating high-temperature alloys.
Heat Treatment Effect on the Corrosion Resistance of 316L Stainless Steel Produced by Laser Powder Bed Fusion
Sangoi, Kevin; Nadimi, Mahdi; Song, Jie; Fu, Yao (MDPI, 2025-01-04)
This study explores the effect of heat treatment on the microstructural characteristics and corrosion resistance of 316L stainless steels (SSs) produced via laser powder bed fusion (L-PBF), focusing on anisotropic corrosion behavior—a relatively less explored phenomenon in LPBF 316L SSs. By systematically analyzing the effects of varying heat treatment temperatures (500 °C, 750 °C, and 1000 °C), this work uncovers critical correlations between microstructural evolution and corrosion properties. The findings include the identification of anisotropic corrosion resistance between horizontal (XY) and vertical (XZ) planes, with the vertical plane demonstrating higher pitting and repassivation potentials but greater post-repassivation current densities. Furthermore, this study highlights reductions in grain size, dislocation density, and melt pool boundaries with increasing heat treatment temperatures, which collectively diminishes corrosion resistance. These insights advance the understanding of processing–structure–property relationships in additively manufactured metals, providing practical guidelines for optimizing thermal post-processing to enhance material performance in corrosive environments.

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