University of Connecticut

Events Calendar

PhD Dissertation Defense

Thursday, May 13, 2021
2:30pm – 4:30pm

Storrs Campus
Video meeting

Graduate Student Erin Curry, Department of Physics, University of Connecticut

Investigations of nonequilibrium processes in additively manufactured metallic alloys and negative thermal expansion materials

Additive manufacturing, also known as 3D printing, is an emergent manufacturing technique capable of realizing novel topologies more efficiently and with more design flexibility than traditional approaches. For laser-based powder bed fusion (LPBF), a high power laser incident on a bed of metallic powder sinters a part in a layer-by-layer construction. While laser-powder interactions are vital to successful build with known microstructure and residual stress states, little is known about the interaction point and the role the melt pool evolution has on the reliability of the final piece. In this talk, I will describe progress in the study of the optical properties of disordered nickel and titanium based additively manufactured alloys, and also present the development of novel sensor technology capable of reading time-dependent temperature profiles on the appropriate time scales. The results of this work provide in-situ monitoring options in LPBF processes, an important fundamental science step needed to bring AM technology into full scale production use.

I will also present my work on a second laser-based interaction nonequilibrium process, ultrafast laser pulse induced strain solitons. Previous experiments have shown that when laser pulses of sufficiently large fluence are incident an opaque transducer film on a substrate the evolution of the induced acoustic strain wave experiences a balance of dispersion and nonlinear elastic properties of the substrate. This balanced evolution yields the formation of solitary strain waves known as solitons, which can be numerically described by the nonlinear differential Korteweg-de Vries (KdV) equation. To my knowledge all such experiments have been performed on conventional positive thermal expansion material substrates. I will present numerical solutions to the KdV equation under the unusual case where the substrate experiences negative thermal expansion and show, using realistic linear and nonlinear parameters, that the emerging solitons are qualitatively different from those through PTE materials in several ways.

Contact:

Prof. J. Hancock

Physics Department (primary), College of Liberal Arts and Sciences, UConn Master Calendar

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