Date and Time:
Fri, 02/16/2018 - 2:30pmSpeaker:
Jeffrey T. LloydAffiliation:
U. S. Army Research Laboratory, Aberdeen, MarylandLocation:
Discovery Park B-155
Abstract:
Since the turn of the century, magnesium has been heralded as a light-weight, structural metal that given sufficient development, could replace aluminum and steel in every day applications. Magnesium is extremely strong, and possesses the highest specific stiffness of any structural metal. Over the past several years, several thousand publications have focused on understanding the prevalent deformation mechanisms, alloy design, and optimal processing conditions – yet fewer than twenty commercially available alloys are in production. Despite significant development, high strength magnesium alloys have limited ductility and low fracture toughness compared with similar aluminum alloys. In this work, novel computational models are developed and used in conjunction with conventional mechanical testing and high resolution microstructural characterization to elucidate the mechanisms that govern material failure in magnesium. Sensitivity of failure to key microstructural features are identified, and possible candidate microstructures are proposed.
Biography:
Dr. Jeffrey T Lloyd received his bachelor’s, master’s, and doctorate degrees in Mechanical Engineering at Georgia Institute of Technology in 2008, 2010, and 2014, respectively. From 2008-2011 he was a NSF Graduate Research Fellow and from 2011-2014 he was a DoD SMART Fellow. His graduate studies focused on developing high rate crystal models to describe the dynamic response of face-centered cubic metals subjected to shock loading conditions. Since then he has been employed as a research scientist at the US Army Research Laboratory in Aberdeen, Maryland and has focused on developing models that describe the strength and failure response of novel materials, e.g., magnesium alloys, nano crystalline materials, high entropy alloys, and additively manufactured materials, as well as understanding how their material behavior can be exploited for protection applications.