institute for materials science - los alamos national ......is par&cularly interested in the...

UNCLASSIFIED

IMSRapidResponse2017*RecipientGuestSeminar

Dr. Levente BaloghCanadianNuclearLaboratories(CNL)

Quantifying irradiation defects in Zr alloys:Acomparisonbetweentransmissionelectronmicroscopy&diffracEonlineprofileanalysis

Thursday,April20,20171:30-2:30MSLAuditorium(TA-03-Bldg1698-RoomA103)

Abstract: Irradia&on induced disloca&ons significantly affect the mechanical proper&es of Zr alloys, altering slip andinfluencing creep and growth. Thus, the quan&ta&ve characterisa&on of irradia&on defects, as a func&on of fluence, cold-work and/or thermal treatments is important for models that aBempt to predict their impact on proper&es. Whole paBerndiffrac&on line profile analysis (DLPA) is a modern tool for microstructure characteriza&on based on first-principle physicalmodels, well-established for disloca&on density measurements in plas&cally deformed materials. However applying theseDLPA methods directly to irradiated materials yields higher than expected disloca&on density values in comparison tohistorical TEM measurements, and to past line broadening analysis studies calibrated to TEM observa&ons. In an effort tounderstand these differences, a new microstructural model was developed for DLPA to specifically address disloca&onstructures consis&ng of ellip&cal <a> and <c>-component loops. To compare the refined DLPA method with TEMmeasurements, high resolu&on neutron diffrac&on paBerns on the unirradiated and irradiated Zr-2.5Nb samples werecollected with the Neutron Powder Diffractometer (NPDF) instrument at the Los Alamos Neutron Science Center (LANSCE),and were evaluated. High resolu&on TEM measurements were performed at the Reactor Materials Tes&ng Laboratory(RMTL), Queen’s University, for comparison to the DLPA results. The capabili&es of both methods will be compared indetail. The main sources of uncertain&es will be discussed, such as the accuracy of the loop diameter measurements andthe presence of residual intergranular strains in the case of TEM and DLPA, respec&vely. It will be shown that thedifferences between the density values provided by DLPA and TEM are inherent to the methods and can be reconciled withtheinterpreta&onofthedata.

Bio: Dr. Balogh is a Research Scien&st at the Radia&on Damage and Deforma&on Branch at the Canadian NuclearLaboratories (CNL) in Chalk River, ON, Canada. He received a Ph.D. in Physics (Materials and Solid State Physics) fromEötvös Loránd University, Budapest, Hungary, and con&nued as a postdoctoral fellow at the Los Alamos Na&onalLaboratory and Queen’s University, Kingston, ON, Canada. His exper&se lies in applying and developing advanced X-ray/synchrotron and neutron diffrac&on based techniques to characterize the structure and microstructure of materials. Heis par&cularly interested in the characteriza&on and quan&fica&on of lacce defect popula&ons using diffrac&on techniqueswithfocusonradia&oninduceddamageinnuclearstructuralmaterials,suchasZr-alloysandsteels.

UNCLASSIFIED - OPEN TO ALL LANL EMPLOYEES

HostedbyDonBrown*MST-8

Sponsored by the Institute for Materials Science

TobeonDr.Balogh'sAgenda,topar&cipateintheEarlyCareerLunch,orforgeneralinforma&oncontact:DonBrown

dbrownl@lanl.gov*667-7904

Institute for Materials Science