Wadley Research Overview


The physical, mechanical, charge transport, and other opto and magnetoelectrical properties of materials are determined by the atoms from which they are assembled, the nature of the inter atom bonds between them, by the geometry (crystallography) of their packing into three dimensional structures (phases), by the defects incorporated within, and between grains of these phases, and by the volume fraction and topology of the many phases often present in advanced materials. The 3D micro (or nano) structures of these high performance materials is controlled by the thermochemical and thermomechanical conditions experienced during processing of the material. Composite materials provide a means for combining two or more of these advanced materials to achieve a new state of matter whose properties (usually but not always) lie between those of each material. Exceptions include the fracture-related properties of composites (which can be superior to those of either of the materials from which they are made) and nanoscopic materials where the very high fraction of "surface" atoms, low dimensionality, and diversity of interatomic bonding can profoundly change particle properties as well as those of the mesomaterials assembled from them.

From time to time, the group has taken on large scale projects to solve challenging engineering problems. For example, the group has integrated heatpipe concepts with cellular materials and sandwich construction to design, construct and test large (several meter) jet blast deflector panel concepts that manage the coupled thermo-mechanical loads due to impinging jet engine exhaust plumes. Analogous jet blast protection systems were also being developed to protect ship decks. The group has also investigated, and developed successful solutions to protect structures from near by explosions in water, air and most recently under soil. This research has led to the development of a new fundamental understanding of shock load interactions with structures, and an interest in ballistic resistant materials.

The group conducts its experimental research in four laboratories which are equipped with state of the art equipment for depositing coatings, fabricating composites and making cellular materials. The group has ample funding from government agencies and occasional industry sponsors.

Haydn Wadley's research group has developed many inventions (21 have been awarded US patents to date) and has spun out two successful companies. One is commercializing vapor deposition technologies (directed vapor deposition and coaxial plasma deposition) for coating gas turbine engine components, while the second is scaling up new cellular lattice materials, and exploring their application for impulsive load mitigation and thermal protection.

It usually has openings for one or two Ph.D. candidates each year.

Research Areas

  • High Temperature Coatings

    EBC, TBC, Multi-Principal Element Refractory Alloy Coatings


    Efforts to increase fuel efficiency and reduce CO2 emissions are driving increases in the temperature at which gas turbine engines operate. Our group is exploring the mechanisms by which current coatings function and eventually fail as the operating temperature rises. It is developing and exploiting state of the art deposition techniques such as electron beam directed vapor and coaxial plasma deposition and plasma spray processes to create coatings that provide much better protection.

     
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  • Simulated Engine Materials Testing

    SiC/SiC composites and Environmental Barrier Coatings


    Combined chemo-thermo-mechanical testing of multilayer-EBCs under simulated engine environments provides a means for assessing candidate engine materials and to understand the mechanisms that govern the effectiveness of these candidate materials. The University of Virginia LSL Simulated Engine Materials Testing Facility has been designed to subject coated CMCs and other engine materials to cyclic thermomechanical stress and thermochemical environments similar to those experienced inside the high pressure combustion/ high pressure turbine of modern gas turbine engines.

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  • Nanocellular materials


    Nature makes pervasive use of cellular materials for our bones, tree trunks, insect exoskeltons, etc. Our group is developing synthetic, topologically optimized cellular materials from high performance materials such as carbon, silicon carbide and aluminum oxide fibers using state of the art polymers and light metallic alloys to interconnect them. These materials/structures have very high specific compressive strengths and offer many opportunities to make lighter structures for automobilies, planes, ships and space vehicles.

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  • Additive Manufacturing of Ultralight Metallic Cellular Structures


    The advent of additive manufacturing has allowed for the processing of metal structures with complex geometries; cellular lattices (similar to foams, but with ordered components) are one class of structures benefitting from novel additive manufacturing methods. 

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  • Ballistic Impact


    The impact of a projectile with a material suddenly creates very large stresses in both the material and the projectile. These stresses then activate mechanisms of deformation (such as dislocation motion and twinning) and fracture in metals and ceramics, and various molecular sliding and chain scission processes in polymers. These are rate dependent and therefore the material and projectile responses are a function of the impact velocity. Our group brings this mechanistic perspective to the design of novel material systems and multi component cellular topologies that impede penetration in lightweight configurations.

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