Speaker: Dr. Kris Darling, U.S. Army Research Laboratory Speaker: Dr. Kris Darling, U.S. Army Research Laboratory

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Speaker: Dr. Kris Darling, U.S. Army Research Laboratory

September 24 @ 11:00 am - 12:00 pm

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Speaker: Dr. Kris Darling, U.S. Army Research Laboratory 

Title: “Thermodynamic and Practical Aspects of Mechanical Alloying and the Mechanical Response of Stabilized Nano Crystalline CuTa Alloys”

Abstract: Although an understanding of the bulk mechanical response of nanocrystalline metals has been pursued intensely for over three decades, much remains a mystery with respect to their true mechanical response. The simultaneous occurrence of extensive, rapid grain growth with deformation results in uncertainty in the knowledge of how these materials would respond if there were no microstructural coarsening. This handicap becomes exponentially problematic as exposure to testing conditions becomes more and more extreme, and the already unstable nanocrystalline microstructures become obliterated under the drastically intensified driving force to rearrange and grow. The difficulty in decoupling the influence of grain growth from their mechanical response has been such a challenge that the inability to do so has given rise to common stigmas (misconceptions), which limit the perceived expectations with regard to the performance capabilities of these new materials by the community. This mind state, however, provides a new frontier for fundamental discovery where opportunities exist to get beyond the perceived mechanical limits which have been called out in this discipline of science. This is most typified when considering the mechanical behavior of nanocrystalline metals under extreme and/or far from equilibrium conditions. This topic along with thermodynamic and practical aspects of mechanical alloying as they pertain to developing stable nanocrystalline alloys will be presented. The immiscible Cu-Ta system will be used to highlight these aspects. 

Biography: Dr. Darling completed his bachelor’s, master’s, and Ph.D. from North Carolina State University under the guidance of Carl Koch and Ron Scattergood. He completed his Ph.D. in 2009 and joined as a postdoctoral fellow at the Army Research Laboratory (ARL) at Aberdeen Proving Ground, MD, where he has been a permanent staff since 2010. While at ARL, Dr. Darling has developed scientific and engineering programs that explore the processing-structure-property relationships in novel structural metals, with particular emphasis on the unique properties that emerge at the nanoscale. His current research concentrates on the thermodynamic and kinetic stabilization of nanocrystalline metals and alloys for defense applications. Dr. Darling has more than 19 years of experience in the fabrication, consolidation, testing, and characterization of nanocrystalline metals and alloys, and he has published more than 140 articles in this area of research.

Details

Date:
September 24
Time:
11:00 am - 12:00 pm
Event Categories:
,

Venue

EB1 – Room 1011
911 Partners Way
Raleigh, NC 27695-7907 United States

Organizer

MSE Department
Phone:
919.515.2377
View Organizer Website

Other

Speaker
Dr. Kris Darling
Host
Dr. Donald Brenner