Abstracts Book - IMRC 2018

• SA2-O001 Invited Talk
THE ROLE OF NON-EQUILIBRIUM GRAIN BOUNDARY STRUCTURE
IN RADIATION TOLERANCE AND THERMAL STABILITY
Mitra L. Taheri 1 , Pete Baldo 2 , Christopher Barr 1 , Jacob Gruber 1 , Marquis Kirk 2 , Garritt Tucker 1 ,
Yong Q. Wang 3 , Gregory Vetterick 1
1
Drexel University, Department of Materials Science & Engineering, United States. 2 Argonne
National Laboratory, , United States. 3 Los Alamos National Laboratory, Ion Beam Materials
Laboratory, United States.
Non-equilibrium grain boundaries contain excess free volume and higher
energy than their equilibrium counterparts with identical macroscopic degrees
of freedom, and may act as efficient sinks for irradiation-induced defects. The
relative sink strengths of equilibrium and non-equilibrium grain boundaries
compared in nanocrystalline materials produced by both magnetron sputtering
and severe plastic deformation under ex situ and in situ ion irradiation. Thermal
stability of severely deformed nanocrystalline materials were examined as a
baseline. The microstructures containing non-equilibrium grain boundaries
retained both a smaller number density of defect clusters and a smaller average
defect cluster size than its equilibrium counterpart. Molecular dynamics
simulations also showed that excess free volume contributes to a decreased
survival rate of point defects. Finally, a case study of grain boundary microstates
and their role in radiation tolerance will be touched upon. Overall, our results
suggest that non-equilibrium grain boundaries act as more efficient sinks for
defects and that such boundaries could be utilized to create more radiation
tolerant materials in the future.
Presenting authors email: mlt48@drexel.edu