Dr. Trenkle’s expertise is in metallurgy with an emphasis on macro- and micro- structural characterization, processing, and mechanical performance of a range of metal alloys, including thin films and coatings used in electronic and mechanical applications. He also has experience in performing detailed failure analysis of these materials after they have been placed into service. Additionally, Dr. Trenkle has studied specialty welding of thermally sensitive materials, characterizing the fracture toughness and fracture surfaces as a function of welding parameters.
Dr. Trenkle has extensive experience conducting and interpreting results from several chemical and microstructural characterization techniques, including x-ray diffraction (XRD), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and x-ray fluorescence (XRF). He is also skilled at developing specialized indentation methods, measuring fracture toughness, and performing differential scanning calorimetry (DSC) in order to characterize the mechanical and thermophysical properties of materials. During his career, he has extensively used magnetron sputtering, electrodeposition (electroplating), and arc welding to produce a variety of metal alloys. Dr. Trenkle also has experience conducting testing in accordance with ASTM and Telcordia standards, often designing specialized testing apparatuses to meet the testing requirements.
Prior to joining Exponent, Dr. Trenkle worked as a process development engineer at Xtalic Corporation where he was responsible for research and development of a new electro-plated metal alloy for use in electronic connectors. He designed and characterized the alloy, chemistry, and process so that the new product could be easily integrated into existing manufacturing systems. He also was a Postdoctoral Associate at Massachusetts Institute of Technology (MIT) where he developed a nanoindenter capable of operating at elevated temperatures in inert atmospheres. Also while at MIT, Dr. Trenkle assisted in teaching undergraduate and graduate courses in mechanical behavior of materials and physical metallurgy.
Rupert TJ, Trenkle JC, Schuh CA. Enhanced solid solution effects on the strength of nanocrystalline alloys. Acta Materialia 2011; 59:1619.
Kelly ST, Trenkle JC, Koerner LJ, Barron SC, Walker N, Pouliquen PO, Tate MW, Gruner SM, Dufresne EM, Weihs TP. Fast x-ray microdiffraction techniques for studying irreversible transformations in materials. Journal of Synchrotron Radiation 2011; 18:464.
Franke O, Trenkle JC, Schuh CA. Temperature dependence of the indentation size effect. Journal of Materials Research 2010; 25:1225.
Trenkle JC, Packard CE, Schuh CA. Hot nanoindention in inert environments. Review of Scientific Instruments 2010; 81:073901.
Packard CE, Trenkle JC, Schuh CA. Nanoindentation: High Temperature. In: Encyclopedia of Materials Science and Technology, Elsevier, pp. 1–6, Oxford, 2010.
Trenkle JC, Koerner LJ, Tate MW, Walker N, Gruner SM, Weihs TP, Hufnagel TC. Time-resolved x-ray microdiffraction studies of phayse transformation during rapidly propagating reactions in Al/Ni and Zr/Ni multilayer foils. Journal of Applied Physics 2010; 107:113511.
Trenkle JC, Koerner LJ, Tate MW, Gruner SM, Weihs TP, Hufnagel TC. Phase transformations during rapid heating of Al/Ni multilayer foils. Applied Physics Letters 2008; 93:081903.
Trenkle JC, Koerner LJ, Tate MW, Gruner SM, Weihs TP, Hufnagel TC. In situ x-ray microdiffraction of phase transformations in rapidly propagating, high-temperature reactions in nanolaminate foils. JANNAF Meeting Proceedings, 2008.
Trenkle JC, Weihs TP, Hufnagel TC. Fracture toughness of bulk metallic glass welds made using nanostructured reactive multilayer foils. Scripta Materialia 2008; 58:315.
Trenkle JC, Wang J, Weihs TP, Hufnagel TC. Microstructural study of an oscillatory formation reaction in nanostructured reactive multilayer foils. Applied Physics Letters 2005; 87:153108.
Presentations
Trenkle JC, Packard CP, Schuh CA. Optimizing the performance of high temperature nanoindention in inert atmospheres. Materials Research Society Fall Meeting, Boston, MA, 2008.
Trenkle JC, Koerner L, Tate MW, Gruner S, Weihs TP, Hufnagel TC. In situ x-ray microdiffraction temporal resolution of phase transformations in rapidly propogating exothermic reactions in nanoscale multilayers. Materials Research Society Fall Meeting, Boston, MA, 2008.
Trenkle JC, Koerner L, Tate MW, Gruner S, Weihs TP, Hufnagel TC. In situ x-ray microdiffraction of phase transformations in rapidly propagating, high-temperature reactions in nanolaminate foils. Oral presentation, JANNAF Meeting, Newton, MA, 2008.
Trenkle JC, Koerner L, Tate MW, Gruner S, Weihs TP, Hufnagel TC. Real-time X-ray diffraction studies of phase transformations during rapidly propagating reactions in nanolaminate foils. Oral presentation, Materials Research Society Fall Meeting, Boston, MA, 2007.
Trenkle JC. Joining metallic glasses using nanostructured reactive multilayer foils. Invited talk, NIST Center for Neutron Research, Gaithersburg, MD, 2007.
Trenkle JC, Koerner L, Nathani H, Tate MW, Gruner S, Weihs TP, Hufnagel TC. Real-time in situ X-ray diffraction of self-propagating exothermic reactions in nanostructured reactive mulitlayer foils. Oral presentation, Materials Research Society Fall Meeting, Boston, MA, 2006.
Trenkle JC, Koerner L, Tate MW, Gruner S, Weihs TP, Hufnagel TC. In situ X-ray diffraction of phase transformations in nanostructured reactive multilayer foils. Oral poster, Synchrotron Radiation in Materials Science-5, Chicago, IL, 2006.
Hufnagel TC, Trenkle JC, Swiston, Jr, AJ, Weihs TP. Welding metallic glass with reactive multilayer foils. Invited talk presented by J.C. Trenkle, The First International Conference on Mechanics and Mechanical Properties of Non-crystalline Materials I: Amorphous Metals, Beijing, China, 2006.
Trenkle JC, Swiston, Jr., AJ, Knio OM, Besnoin E, Duckham A, Weihs TP, Hufnagel TC. Joining metallic glass using reactive multilayer foils. Oral presentation, Johns Hopkins Materials Science Research Symposium, Baltimore, MD, 2005.
Trenkle JC, Wang J, Knio OM, Besnoin E, Weihs TP, Hufnagel TC. Producing amorphous joints in metallic glasses by reactive joining. Oral presentation, The Minerals, Metals & Materials Society Annual Meeting, San Francisco, CA, 2005.
Duckham A, Trenkle JC, Swiston, Jr., AJ, Knio OM, Besnoin E, Hufnagel TC, Weihs TP. Amorphous product formation by self-propagating reactions in multilayered foils. Oral presentation, Materials Research Society Fall Meeting, Boston, MA, 2003.