About

Haydn N. Wadley is a University Professor and the Edgar A. Starke Professor of Materials Science and Engineering at the University of Virginia. His broad interests encompass materials science, composite materials, micromechanics, and thermal transport. His current research explores high temperature thermal and environmental coatings systems, microarchitectured materials including those with lattice and inverse opal topologies, entropy stabilized refractory metal alloys, and rare earth silicates. Wadley's work addresses fundamental questions related to the atomic assembly of nanoscopic materials from the vapor phase, the topological structuring of cellular materials, and the processing of high temperature coatings and composites. His research has contributed to the improved design of thermal and environmental barrier coatings for gas turbine engines, liquid metal heat plates for hypersonic vehicle leading edges, passive jet blast deflector concepts, and various materials and structures for mitigating high intensity dynamic loads such as ballistic impact and blast shock.

Research topics

• Materials science
• Metallurgy
• Composite material
• Chemical engineering
• Thermodynamics
• Nanotechnology
• Computational chemistry

Selected publications

• Octet truss lattices fabrication via a layer-by-layer stacking manufacturing approach: Mechanical properties of the Al6061-T6 lattices

  Composites Communications · 2025-11-20

  articleSenior author
  PublisherDOI

• Two doping strategies for modifying radiative transport in ZrO2-YTaO4 thermal barrier coating materials

  Acta Materialia · 2025-02-06 · 7 citations

  articleSenior authorCorresponding
  PublisherDOI

• Accelerating materials discovery in heterogeneous composition-property design spaces via collaborative Bayesian optimization

  Materials & Design · 2025-12-17 · 1 citations

  articleOpen access

  • Consensus-based multi-agent Bayesian optimization (BO) explores heterogeneous spaces. • Collaboration boosts efficiency, benchmarks show when simpler BO suffices. • Multi-agent BO accelerates discovery of HfTiTaNb alloys with target properties. Adaptive learning implementations for materials design are challenged by the complex, nonlinear relationships between composition and properties, particularly in high-performance applications such as high-temperature compositionally complex refractory alloys. Traditional Bayesian optimization (BO) methods, which typically rely on a single Gaussian Process (GP) surrogate, often struggle to model heterogenous behaviors across the design domain. To address this limitation, we introduce collaborative BO as a multi-agent framework for materials discovery. In the context of optimizing compositions for desired properties, each agent models a specific subregion of the design space, where subregions share similar property trends, and exchanges information with the other agents to expedite exploration and design optimization. Comparative evaluations demonstrate that, when compared to single-agent BO and other approaches discussed in this article multi-agent BO allows flexible information-sharing protocols and effectively reduces iterations of adaptive learning while reliably delivering designs that meet the targeted mechanical properties. These findings provide novel insights into the behavior of refractory multi-component alloys, using the Hf-Ti-Ta-Nb system as a case study, and illustrate the potential of adaptive multi-agent learning in efficiently screening extensive materials libraries. Moreover, the framework is broadly applicable to other problems characterized by diverse data sources, where advanced optimization strategies are essential for accelerated materials discovery.

  PublisherDOI

• A high temperature engine materials test facility

  Review of Scientific Instruments · 2024-04-01 · 7 citations

  articleSenior author

  Gas turbine engines subject materials to extreme conditions. Their high temperature materials and co-developed coatings must survive combustion gas temperatures currently approaching 1800 °C, large thermal gradients, severe thermal shock, and static and fatigue inducing applied stresses, all the while operating in highly reactive, high-pressure, high-speed combustion gas flows containing significant partial pressures of water vapor, oxygen, and other reactive species for many tens of thousands of hours. We describe the design and development of a test facility for the study of materials under individual and combinations of test parameters similar to those experienced within legacy and future engines. A hydraulic load frame capable of applying static or cyclic tension-compression stresses up to 400 MPa to flat-dog bone-shaped test specimens is integrated within an environmental test chamber capable of sustaining gas pressures from 0.1 to 1.2 MPa (1-12 atm). An adjustable 0.1-2 kW power CO2 laser whose 10.6 µm wavelength radiation is strongly absorbed by ceramic coating materials is used to heat sample surfaces to temperatures of 1800 °C and above, while rear surface air jet cooling establishes through-thickness thermal gradients. Rapid laser heating in conjunction with transiently applied front and/or rear-side air cooling is used to create hot or cold thermal shock effects. This is accompanied by the impingement of a high pressure (up to 1.3 MPa) reactive gas jet upon the sample with speeds up to 300 m/s by preheating dry air, mixing it with steam to the desired humidity, heating to 850 °C, and then expanding it through a converging nozzle. Thermal imaging pyrometers measure specimen front and back surface temperature fields, while environmental test chamber view ports permit digital image correlation and strain mapping.

  PublisherDOI

• Underexcitation prevents crystallization of granular assemblies subjected to high-frequency vibration

  Proceedings of the National Academy of Sciences · 2023-07-10 · 3 citations

  articleOpen access

  Crystallization of dry particle assemblies via imposed vibrations is a scalable route to assemble micro/macro crystals. It is well understood that there exists an optimal frequency to maximize crystallization with broad acceptance that this optimal frequency emerges because high-frequency vibration results in overexcitation of the assembly. Using measurements that include interrupted X-ray computed tomography and high-speed photography combined with discrete-element simulations we show that, rather counterintuitively, high-frequency vibration underexcites the assembly. The large accelerations imposed by high-frequency vibrations create a fluidized boundary layer that prevents momentum transfer into the bulk of the granular assembly. This results in particle underexcitation which inhibits the rearrangements required for crystallization. This clear understanding of the mechanisms has allowed the development of a simple concept to inhibit fluidization which thereby allows crystallization under high-frequency vibrations.

  PublisherOA PDFDOI

• Noise reduction and peak detection in x-ray diffraction data by linear and nonlinear methods

  Journal of Vacuum Science & Technology B Nanotechnology and Microelectronics Materials Processing Measurement and Phenomena · 2023-06-06 · 6 citations

  article

  Considerable progress has been made in the last few years in removing white noise from visible–near-ultraviolet (UV/VIS) spectra while leaving information intact. For x-ray diffraction, the challenges are different: detecting and locating peaks rather than line shape analysis. Here, we investigate possibilities of state-of-the-art UV/VIS methods for noise reduction, peak detection, and peak location applied to x-ray diffraction data, in this case, data for a ZrO2 −33 mol. % TaO4 ceramic. The same advantages seen in UV/VIS spectroscopy are found here as well.

  PublisherDOI

• Mechanical property—processing relations for SiC foams synthesized via polymer particle templating of polycarbosilane

  International Journal of Ceramic Engineering & Science · 2023-12-20

  articleOpen accessSenior author

  Abstract Silicon carbide foams with an average pore diameter of 650 nm and an inter‐pore ligament thickness of 150 nm have been synthesized using spherical polymethylmethacrylate (PMMA) particle templating of a β‐SiC nanoparticle‐loaded polycarbosilane (PCS) preceramic polymer and the effect of crystallization temperature upon their microstructure and mechanical properties investigated. Differential scanning calorimetry and thermogravimetric analysis were used to investigate both the kinetics of PMMA decomposition and the influence of β‐SiC nanoparticles upon the mechanisms of PCS cure, pyrolysis, and partial crystallization. As the crystallization temperature was systematically increased, the inter‐pore ligament structure coarsened and nanopores developed within the ligaments between the β‐SiC nanoparticles. The foam's Young's modulus and compressive strength at first increased with crystallization temperature, reaching a maximum after processing at 1300˚C. However, further increases in temperature resulted in a rapid fall in both foam modulus and compressive strength. To gain insight into the fundamental processes responsible for the overall (macroscale) mechanical properties, models for open/closed cell foams were inverted and used in conjunction with the measured foam density, Young's modulus, and compressive strength to estimate the mechanical properties of the inter‐pore ligaments. This procedure indicated that changes to the ligament properties were responsible for the observed dependence of the foam mechanical properties upon crystallization temperature.

  PublisherOA PDFDOI

• Gravity enables self‐assembly

  Natural Sciences · 2022-05-31 · 1 citations

  articleOpen access

  Abstract Crystallization of granular assemblies has broad implications for rapid and scalable creation of architected materials with applications ranging from structural materials to microarchitected battery electrodes. While significant advances have been made in understanding colloidal self‐assembly at nano to micro scale, the governing mechanisms for organization of dry assemblies of hard spheres remain unclear. Here, we investigate crystallization of mono‐size hard spheres with and without imposed vibration. Using X‐ray computed tomographic analysis coupled with discrete‐element simulations, we unravel the roles of gravity and imposed vibration on the three‐dimensional self‐assembly of the dry spheres. We use these insights to introduce gravity‐mediated epitaxial crystal growth with slow pouring of balls on seeding templates. Contrary to vibration‐induced crystallization, this method can form large single crystals with both close‐packed and rather surprisingly, nonclose‐packed metastable particle arrangements. Our results provide insight for the scalable manufacture of defect‐free granular assemblies that can be used as space‐holding templates to manufacture cellular materials, such as inverse opals and other related topologies. Key points Self‐assembly of hard spheres is a critical step for the scalable manufacture of micro‐architected solids. Via a combination of vibration experiments, 3D X‐ray tomographic observations, and simulations, we elucidate the critical role of gravity in the self‐assembly of hard spheres. We design seeding templates that can not only induce the self‐assembly into stable close‐packed crystal structures but also rather counterintuitively into metastable single crystal structures.

  PublisherOA PDFDOI

• Author response for "Gravity enables self‐assembly"

  2022-04-29

  peer-review
  PublisherDOI

• Failure mechanisms in model thermal and environmental barrier coating systems

  Journal of the European Ceramic Society · 2022-04-27 · 53 citations

  articleSenior author
  PublisherDOI

Frequent coauthors

• V.S. Deshpande

  53 shared

• Xiaowang Zhou

  Sandia National Laboratories California

  50 shared

• Kumar P. Dharmasena

  University of Virginia

  40 shared

• D.M. Elzey

  34 shared

• Hengbei Zhao

  27 shared

• Douglas T. Queheillalt

  University of Virginia

  23 shared

• A.G. Evans

  University of Liverpool

  23 shared

• D.T. Queheillalt

  University of Virginia

  20 shared

Labs

• Wadley Intelligent Processing Materials GroupPI

Awards & honors

• VASEM Elects UVA Engineering Faculty and Alumna to Membershi…