Research Topics
Additive Manufacturing of Refractory Alloys
Extreme environments require high-temperature structural materials capable of withstanding intense heat fluxes and stresses. Refractory metals are an attractive option due to their high melting temperatures and structural integrity; however, there is an unmet need for alloys that can be manufactured for use in >1400°C environments. Laser-based manufacturing offers the dual benefits of significantly reducing both processing time and the amount of feedstock material required to produce crucial components. We are developing laser parameters for Nb, Ta, and W alloys, characterizing their microstructures, and measuring their high-temperature tensile properties to elucidate the processing-structure-property relationships in additively manufactured refractory metals. This approach aims to rapidly screen and develop novel refractory alloys for deployment in the nation’s most critical platforms.
Compositionally Graded Interfaces
Recent fabrication advances enable precise control of microstructures, compositions, and phases across various length scales within a monolithic material. Graded interfaces offer an opportunity to enhance interfacial toughness and minimize residual stresses. This is particularly relevant in extreme environments—such as those in the energy, transportation, and space sectors—where materials endure complex thermomechanical loading and environmental degradation. Our collaborative effort combines laser additive manufacturing, process and phase modeling, and location-specific measurements to assess how processing, microstructure, and local properties influence the optimal interfacial length scale for GRCop-42/IN625 interfaces. As we transition from discrete to continuously graded interfaces with increasing interfacial widths, we aim to clarify the interactions among graded composition, microstructure, and properties to establish the representative volume element needed for capturing interfacial behavior in full-scale manufacturing
Collaborators: Kevin Hemker (Johns Hopkins University), Alex Lark
Shape Memory Alloys
Shape memory alloys (SMAs) are a unique class of functional materials governed by the reversible martensitic phase transformation. Superelastic SMAs, such as nickel-titanium and copper-aluminum alloys, exhibit the necessary phase transformation enthalpy to produce a temperature change when mechanically loaded, advancing solid-state cooling technologies and green refrigerants. We are developing novel Cu-base SMAs with significantly reduced critical stress compared to NiTi, enabling smaller actuators for compact elastocaloric devices. This is part of a highly collaborative ERC – Environmentally Applied Refrigerant Technology Hub (EARTH) – which is spearheading research and development in sustainable refrigerant systems.
Collaborators: Ichiro Takeuchi, Damena Agonafer (University of Maryland)
ERC Collaborators: University of Kansas, University of Notre Dame, University of Maryland, University of Hawai’i, University of South Dakota, and Lehigh University
Funding Sources
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