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Elizabeth Stephens

Elizabeth Stephens

Pacific Northwest National Laboratory
PO Box 999
Richland, WA 99352

Biography

Since she joined the Energy Materials Group in 2002, research scientist Elizabeth Vela Stephens is an integral part of a multi-disciplinary team of scientists and engineers working on behalf of the Department of Energy (DOE) to improve the energy efficiency of vehicles and energy conversion systems. She leads programmatic efforts to understand the environmental degradation of materials and to develop joining and processing methods for advanced lightweight, high strength materials that can be used in a cost-competitive manner to manufacture automobiles and on-road trucks. Elizabeth’s work also contributes to the DOE’s Solid State Energy Conversion Alliance program through efforts to develop solid state oxide fuel cells for stationary applications. She has a strong understanding of associated automotive, truck, aerospace, and other industrial manufacturing technologies and has extensive hands-on laboratory experience, with particular emphasis on experimental test design and methods. Elizabeth has authored or co-authored 16 journal articles, 17 conference proceedings, and 40 technical reports internal to the client.

Research Interests

  • Material characterization and performance
  • Joining of materials
  • Metals formability
  • Corrosion

Education and Credentials

  • B.S. Metallurgical Engineering, University of Washington

Selected Publications

2016

  • Cheng G, EI Barker, EV Stephens, KS Choi, and X Sun. 2016. "Quantifying Grain Level Stress-Strain Behavior for AM40 via Instrumented Microindentation." MRS Advances 1(12):761-722.  doi:10.1557/adv.2016.25
  • Cheng G, EI Barker, EV Stephens, KS Choi, and X Sun. 2016. "Quantifying Grain Level Stress-Strain Behavior for AM40 via Instrumented Microindentation." MRS Advances 1(12):761-772.  doi:10.1557/adv.2016.25
  • Prabhakaran R, JP Choi, EV Stephens, D Catalini, CA Lavender, and A Rohatgi. 2016. "Mechanical Characterization and Corrosion Testing of X608 Al Alloy." Chapter 24 in Light Metals 2016, ed. E. Williams, pp. 145-150.  John Wiley & Sons, Inc., Hoboken, NJ. 

2015

  • Upadhyay P, A Rohatgi, EV Stephens, RW Davies, and D Catalini. 2015. "HIGH-RATE FORMABILITY OF HIGH-STRENGTH ALUMINUM ALLOYS: A STUDY ON OBJECTIVITY OF MEASURED STRAIN AND STRAIN RATE." In Light Metals 2015: Proceedings of the symposia sponsored by the TMS Aluminum Committee at the TMS 2015 Annual Meeting & Exhibition, March 15-19, 2015, Orlando, Florida, ed. M Hyland, pp. 327-332.  John Wiley & Sons, Inc, Hoboken, NJ.  doi:10.1002/9781119093435.ch55
  • Chou YS, EV Stephens, Z Xu, W Xu, BJ Koeppel, and JW Stevenson. 2015. Mitigation and Prediction of Spallation of Oxide Scales on Ferritic Stainless SteelPNNL-24025, Pacific Northwest National Laboratory, Richland, WA. 

2014

  • Rohatgi A, A Soulami, EV Stephens, RW Davies, and MT Smith. 2014. "An Investigation of Enhanced Formability in AA5182-O Al During High-Rate Fre-Forming at Room-Temperature: Quantification of Deformation History." Journal of Materials Processing Technology 214(3):722732.  doi:10.1016/j.jmatprotec.2013.07.015
  • Rohatgi A, RW Davies, EV Stephens, A Soulami, and MT Smith. 2014. "An Experimental and Modeling Investigation on High-Rate Formability of Aluminum." Chapter 38 in Light Metals 2014, February 16-20, 2014, San Diego, California, ed. J Grandfield, pp. 219-225.  John Wiley & Sons, Hoboken, NJ.  doi:10.1002/9781118888438.ch38
  • Chou YS, JP Choi, W Xu, EV Stephens, BJ Koeppel, JW Stevenson, and E Lara-Curzio. 2014. Compliant Glass Seals for SOFC StacksPNNL-23397, Pacific Northwest National Laboratory, Richland, WA. 

2013

  • Rohatgi A, EV Stephens, RW Davies, and MT Smith. 2013. "AN INVESTIGATION OF SHEET METAL DEFORMATION BEHAVIOR DURING ELECTRO-HYDRAULIC FORMING (EHF)." In ASME 2013 Manufacturing Science and Engineering Conference (MSEC 2013), June 10-14, 2013, Madison, Wisconsin, vol. 1, pp. V001T01A011 Paper No. MSEC2013-1129.  ASME, New York, NY.  doi:10.1115/MSEC2013-1129
  • Stevenson JW, EM Riel, EV Stephens, and MA Khaleel. 2013. Surface Treatments for Improved Performance of Spinel-coated AISI 441 Ferritic Stainless SteelPNNL-22191, Pacific Northwest National Laboratory, Richland, WA. 

2012

  • Rohatgi A, EV Stephens, DJ Edwards, MT Smith, and RW Davies. 2012. "Electro-hydraulic forming of advanced high-strength steels: Deformation and microstructural characterization." In ASME Manufacturing Science and Engineering Conference (MSEC2012), June 4-8, 2012, Notre Dame, Indiana, no. MSEC2012-7322, pp. 163-168.  ASME, New York, NY.  doi:10.1115/MSEC2012-7322
  • Rohatgi A, EV Stephens, RW Davies, MT Smith, A Soulami, and S Ahzi. 2012. "Electro-Hydraulic Forming of Sheet Metals: Free-forming vs. Conical-die Forming." Journal of Materials Processing Technology 212(5):1070-1079.  doi:10.1016/j.jmatprotec.2011.12.014
  • Xu W, EV Stephens, X Sun, MA Khaleel, and HM Zbib. 2012. "Development of a Mechanistic-Based Healing Model for Self-Healing Glass Seals." In 13th Annual Solid State Energy Conversion Alliance (SECA) Workshop, July 24-27, 2012, Pittsburgh, PA.  National Energy Technology Laboratory, Pittsburgh, PA. 
  • Xu W, X Sun, EV Stephens, I Mastorakos, MA Khaleel, and HM Zbib. 2012. "A Mechanistic-Based Healing Model for Self-Healing Glass Seals Used in Solid Oxide Fuel Cells." Journal of Power Sources 218:445-454.  doi:10.1016/j.jpowsour.2012.07.018

2011

  • Koeppel BJ, EV Stephens, and MA Khaleel. 2011. "Optimization of Stack Load Path and Contact Materials." Chapter III.G.3 in 2011 Office of Fossil Energy Fuel Cell Program Annual Report, vol. DOE/NETL-2012-1525, pp. 202-206.  Department of Energy, Washington, DC. 
  • Koeppel BJ, WN Liu, EV Stephens, and MA Khaleel. 2011. "NUMERICAL MODELING OF CATHODE CONTACT MATERIAL DENSIFICATION." Chapter 16 in Advances in Solid Oxide Fuel Cells VII: Ceramic Engineering and Science Proceedings, 8th International Symposium on Solid Oxide Fuel Cells: Materials, Science, and Technology, vol. 32, no. 4, ed. NP Bansal, et al, pp. 171-182.  John Wiley & Sons, Hoboken, NJ.  doi:10.1002/9781118095249.ch16
  • Rohatgi A, EV Stephens, A Soulami, RW Davies, and MT Smith. 2011. "Experimental Characterization of Sheet Metal Deformation During Electro-Hydraulic Forming." Journal of Materials Processing Technology 211(11):1824-1833.  doi:10.1016/j.jmatprotec.2011.06.005
  • Khaleel MA, X Sun, EV Stephens, KP Recknagle, EM Ryan, BJ Koeppel, and C Lai. 2011. "SOFC Modeling and Simulation Tools." Chapter III.G.2 in 2011 Office of Fossil Energy Fuel Cell Program Annual Report, vol. DOE/NETL-2012-1525, pp. 198-201.  Department of Energy, Washington DC, DC. 
  • Liu WN, X Sun, EV Stephens, and MA Khaleel. 2011. "EFFECT OF METALLIC INTERCONNECT THICKNESS ON ITS LONG-TERM PERFORMANCE IN SOFCS." In Advances in Solid Oxide Fuel Cells VII: Ceramic Engineering and Science Proceedings, January 23-28, 2011, Daytona Beach, Florida, vol. 32, ed. NP Bansal, et al, pp. 131-138.  John Wiley & Sons, Inc., Hoboken, NJ.  doi:10.1002/9781118095249.ch12
  • Liu WN, X Sun, EV Stephens, and MA Khaleel. 2011. "Effect of Substrate Thickness on Oxide Scale Spallation for Solid Oxide Fuel Cells." Corrosion Science 53(7):2406-2412.  doi:10.1016/j.corsci.2011.03.025
  • Liu WN, X Sun, EV Stephens, and MA Khaleel. 2011. "EFFECT OF SURFACE CONDITION ON SPALLATION BEHAVIOR OF OXIDE SCALE ON SS 441 SUBSTRATE USED IN SOFC." In Ceramic Transactions: Advances in Materials Science for Environmental and Nuclear Technology II - Materials Science and Technology Conference and Exhibition, (MS&T 2010), October 17-21, 2010, Houston, Texas, vol. 227, ed. SK Sundaram, et al, pp. 81-86.  John Wiley & Sons, Inc., HOBOKEN, NJ.  doi:10.1002/9781118144527.ch9
  • Liu WN, X Sun, EV Stephens, and MA Khaleel. 2011. "Interfacial Shear Strength of Oxide Scale and SS 441 Substrate." Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science 42(5):1222-1228.  doi:10.1007/s11661-010-0537-3

2010

  • Rohatgi A, EV Stephens, A Soulami, RW Davies, and MT Smith. 2010. "High-Strain-Rate Forming of Aluminum and Steel Sheets for Automotive Applications ." In Proceedings of the International Deep Drawing Group Conference (IDDRG-2010 ), May 31-June 02, 2010, Graz, Austria.  International Deep Drawing Research Group, Brussels, Belgium. 
  • Khaleel MA, X Sun, WN Liu, EV Stephens, KP Recknagle, EM Ryan, BJ Koeppel, and C Lai. 2010. "SOFC Modeling and Simulation Tools." Chapter III.G.2 in 2010 Office of Fossil Energy Fuel Cell Program Annual Report, vol. DOE/NETL-2010/1439, pp. 215-219.  Department of Energy, Washington DC. 
  • Liu WN, X Sun, EV Stephens, and MA Khaleel. 2010. Investigation of Performance of SCN-1 Pure Glass as Sealant Used in SOFC PNNL-19407, Pacific Northwest National Laboratory, Richland, WA. 
  • Stephens EV, MT Smith, GJ Grant, and RW Davies. 2010. Forming Limits of Weld Metal in Aluminum Alloys and Advanced High-Strength SteelsPNNL-19912, Pacific Northwest National Laboratory, Richland, WA. 

2009

  • Liu WN, X Sun, BJ Koeppel, EV Stephens, and MA Khaleel. 2009. "Creep Behavior of Glass/Ceramic Sealant and its Effect on Long-term Performance of Solid Oxide Fuel Cells." International Journal of Applied Ceramic Technology 8(1):49-59.  doi:10.1111/j.1744-7402.2009.02455.x
  • Liu WN, X Sun, EV Stephens, and MA Khaleel. 2009. "Life Prediction of Coated and Uncoated Metallic Interconnect for Solid Oxide Fuel Cell Applications ." Journal of Power Sources 189(2):1044-1050.  doi:10.1016/j.jpowsour.2008.12.143
  • Liu WN, X Sun, EV Stephens, and MA Khaleel. 2009. "Quantifying the Interfacial Strength of Oxide Scale and SS 441 Substrate Used in SOFC." In Materials Science & Technology 2009 Conference and Exhibition (MT&S 2009), October 25-29, 2009, Pittsburgh, Pennsylvania, pp. 338-347.  John Wiley & Sons, Inc., HOBOKEN, NJ. 
  • Stephens EV, JS Vetrano, BJ Koeppel, YS Chou, X Sun, and MA Khaleel. 2009. "Experimental characterization of glass-ceramic seal properties and their constitutive implementation in solid oxide fuel cell stack models ." Journal of Power Sources 193(2):625-631. 

2008

  • Sun X, EV Stephens, and MA Khaleel. 2008. "Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds under Lap Shear Loading Conditions." Engineering Failure Analysis 15(4):356-367.  doi:10.1016/j.engfailanal.2007.01.018
  • Sun X, EV Stephens, and MA Khaleel. 2008. "STRAIN RATE AND TEMPERATURE DEPENDENT BEHAVIORS FOR TRANSFORMATION INDUCED PLASTICITY (TRIP) STEELS." In Mechanics & Mechanisms of Finite Plastic Deformation. 14th International Symposium on Plasticity & its Current Applications, Jan. 3-8, 2008, Kona, Hawaii, pp. 247-249.  NEAT Press, Clarksville, MD. 
  • Sun X, WN Liu, EV Stephens, and MA Khaleel. 2008. "Determination of Interfacial Adhesion Strength between Oxide Scale and Substrate for Metallic SOFC Interconnects ." Journal of Power Sources 176(1):167-174.  doi:10.1016/j.jpowsour.2007.10.027

2007

  • Sun X, EV Stephens, and MA Khaleel. 2007. "Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds." Welding Journal 86(1):18s-25s. 
  • Sun X, EV Stephens, and MA Khaleel. 2007. "Effects of Fusion Zone Size on Failure Modes and Performance of Advanced High Strength Steel Spot Welds (2006-01-0531)." SAE Transactions. Journal of Materials & Manufacturing 115(Part 5):509-516. 
  • Sun X, EV Stephens, and MA Khaleel. 2007. "Effects of Manufacturing Processes and In-Service Temperature Variations on the Properties of TRIP Steels." In Society of Automotive Engineers World Congress and Exhibition, pp. 2007-01-0793.  Society of Automotive Engineers, Warrendale, PA. 
  • Sun X, EV Stephens, and MA Khaleel. 2007. "Fatigue Behaviors of Self-Piercing Rivets Joining Similar and Dissimilar Sheet Metals ." International Journal of Fatigue: materials, structures, components 29:370-386. 

2006

  • Grant GJ, RW Davies, EV Stephens, S Wazny, L Kaunitz, and DJ Waldron. 2006. "The Formability of Friction Stir Welds in Automotive Stamping Environments." SAE Transactions. Journal of Materials & Manufacturing V114-5:619-629. 
  • Sun X, EV Stephens, and MA Khaleel. 2006. "Effects of Fusion Zone Size on Failure Modes and Performance of Advanced High Strength Steel Spot Welds." In SAE World Congress & Exhibition 2006, pp. Art. No.: 2006-01-0531.  Society of Automotive Engineers, Warrendale, PA. 
  • Sun X, EV Stephens, RW Davies, MA Khaleel, and DJ Spinella. 2006. "Effects of Failure Modes on Strength of Aluminum Resistance Spot Welds." SAE Transactions. Journal of Materials & Manufacturing V114-5:493-502. 

2005

  • Grant GJ, RW Davies, EV Stephens, wazny, L Kaunitz, and D Waldron. 2005. "The Formability of Friction Stir Welds in Automotive Stamping Environments ." In SAE 2005 World Congress, Advances in Welding and Friction Stir Welding for Automotive Applications, in Detroit, published as WELDING, SAE SP-1959, pp. 141-152.  SAE International, Warrendale, PA. 
  • Stephens EV, GJ Grant, RW Davies, S Wazny, L Kaunitz, B Fulbright, and D Waldron. 2005. "Evaluation of the Mechanical Performance of Self-Piercing Rivets in Friction Stir Welded Structures." In Advances in Welding and Friction Stir Welding for Automotive Applications: Society of Automotive Engineers 2005 World Congress, April 11-14, 2005, Detroit, Michigan, vol. SP-1959, pp. 153-158.  SAE International, Warrendale, PA. 
  • Sun X, EV Stephens, RW Davies, MA Khaleel, and DJ Spinella. 2005. "Effects of Failure Modes on Strength of Aluminum Resistance Spot Welds." In Welding. SAE 2005 World Congress, April 11-14, 2005, Cobo Center, Detroit, MI, USA. Advances in Welding and Friction Stir Welding for Automotive Applications, pp. 47-56.  SAE International, Warrendale, PA. 

2004

  • Sun X, EV Stephens, and DR Herling. 2004. "Static and Fatigue Strength Evaluations for Bolted Composite/Steel Joints for Heavy Vehicle Chassis Components." In 4th Annual SPE Automotive Composites Conference, Commercial Transport Session, Paper No. 3, pp. 1-14.  Society of Plastics Engineers, Brookfield, CT. 
  • Sun X, EV Stephens, MA Khaleel, H Shao, and M Kimchi. 2004. "Resistance Spot Welding of Aluminum Alloy to Steel with Transition Material - From Process to Performance - Part I: Experimental Study ." Welding Journal 83(6):188S-1195S. 
  • Sun X, EV Stephens, MA Khaleel, H Shao, and M Kimchi. 2004. "Resistance Spot Welding of Aluminum Alloy to Steel with Transition Material - From Process to Performance." In Sheet Metal Welding Conference XI, May 11-14, 2004, Sterling Heights, Michigan, ed. Menachem Kimchi and Wanda Newman, p. 18 pp.  American Welding Society, Sterling Heights, MI. 
  • Sun X, EV Stephens, RW Davies, MA Khaleel, and DJ Spinella. 2004. "Effects of Fusion Zone Size on Failure Modes and Static Strength of Aluminum Resistance Spot Welds." Welding Journal 83(11):308s-318s. 

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