Sandra Stangebye

  • Program Year: 1
  • Academic Institution: Georgia Institute of Technology
  • Field of Study: Material Science and Engineering
  • Academic Advisor: Josh Kacher
  • Practicum(s):
    Sandia National Laboratories, New Mexico (2021)
  • Degree(s):
    B.S. Chemical Engineering, University of New Mexico, 2018

Summary of Research

My research involves investigating the deformation mechanisms active in nanocrystalline (NC) and ultrafine grained (UFG) metal thin films. These small-scale materials are typically used as structural components or electrical contacts in micro electromechanical system (MEMS) devices. Operational demands on the thin films can lead to mechanical or thermal stresses that may result in plasticity, friction, fatigue, fracture, etc. Because of this, continued research into the deformation mechanisms leading to failure is required in order to create more robust materials capable of withstanding adverse conditions. My research accomplishes this by utilizing an advanced in situ TEM nanomechanical testing technique that allows for the real-time observation of deformation and simultaneous measurement of material response, such as stress and strain. Plastic deformation in conventional metals (with grain sizes larger than 1 micrometer) is dictated by the glide of line defects (dislocations) through the grain interiors This behavior is not expected in NC and UFG metals due to the high volume of grain boundaries (GBs) that restrict dislocation glide which leads to an observed increase in yield strength of NC and UFG metals. The small grain sizes of these materials lead to unique deformation mechanisms with an increasing contribution from GBs, such as dislocation emission/absorption at GBs, GB sliding, GB migration, etc. My work specifically focusses on identifying the rate-controlling deformation mechanisms in both NC Aluminum and UFG Gold thin films in order to develop a more thorough understanding of the mechanisms that dictate the mechanical properties of these thin metallic films.

Publications

Publications:

Gupta, S., Stangebye, S., Jungjohann, K., Boyce, B., Zhu, T., Kacher, J., Pierron, O., "In situ TEM measurement of activation volume in ultrafine grained gold," Nanoscale 12 (2020) 7146-7158

Stangebye, S., Zhang, T., Gupta, S., Hosseinian, E., Yu, F., Barr, C., Hattar, K., Pierron, O., Kacher, J., "Grain growth of nanocyrstalline aluminum under tensile deformation: a combined in situ TEM and atomistic study," (manuscript submitted for review)

Conference Presentations (Oral):

Stangebye, S., Gupta, S., Pierron, O., Kacher, J., "In Situ TEM MEMS-Based Tensile Nanomechanical Testing of Ultrathin Films," MRS Spring Meeting, 2019.

Stangebye, S., Muntifering, B., Tandon, R., Hattar, K., Snow, C., "Helium Bubble Accelerated Aging," Rio Grande Symposium on Advanced Materials, 2016.

Stangebye, S., Muntifering, B., Paisley, E., Tandon, R., "Microstructural Characterization of Semi Conductive Coating on Ceramic Insulators for Improved High Voltage Hold off Performance," Rio Grande Symposium on Advanced Materials, 2017.

Conference Presentations (Poster):

Stangebye, S., Gupta, S., Zhang, Y., Kacher, J., Pierron, O., Zhu, T., "Investigation of Grain Boundary and Dislocation Interactions Through In-situ TEM MEMS-based Tensile Nanomechanical Testing of Ultrafine Grained Gold Thin Films," TMS 2020

Stangebye, S., Kacher, J., Pierron, O., "Investigating grain growth in nanocyrstalline aluminum using in situ TEM MEMS-based nano mechanical testing," Center for Nanophase Material Science User Meeting 2020 (virtual).

Awards

NSF Graduate Research Fellowship 2020 (Declined)
Best Student Poster Award, CNMS User Meeting 2020
Dean's List, U of New Mexico, 2014-2018 (all semesters)
Regent Scholar, U of New Mexico, 2014-2018