August 2012

Journal

Characterization of a grain size refinement process in cast uranium

By:
Garlea, Elena ; Bridges, R.; Garlea, Vasile O; Carpenter, D. A.; Hemphill, M.; Morrell, J
Journal Name:
Materials Science and Engineering A
Page Number:
210-216
Volume:
559
Issue Number:
N/A
Publication Date:
August 2012
View DOI Listing:
https://doi.org/10.1016/j.msea.2012.08.082

Abstract

The refinementofcoarsegrainsincasturaniumcanleadtowrought-likeproperties.Inthisstudy,a bquenchedprocessiscoupledwithashock-loadingtechniqueand a-annealingtomanipulateuranium’s grain sizeandtheresultingmicrostructureshavebeencharacterized.Neutronpowderdiffractionhas been usedtoevaluatetheresidualstrainaccumulatedfromthethermo-mechanicaltreatments.Optical microscopyandelectronbackscattering(EBSD)inscanningelectronmicroscopyhavebeenemployed to evaluatethegrainsizevariationandthenatureofdeformationmechanisms,respectively.Large strain anisotropyatthelatticelevelwasobservedonshock-loadedspecimens.Thefinalstressrelief annealingdidnoteliminatealltheresidualstrain.Slipandtwinningwereobservedopticallyonthe shockedspecimenswhileEBSDindicatesthatalthough{130},{172},and{112}deformationtwinswere identified,anunusualtypeoftwinning‘{176}’/o5124 was foundtobedominant.Itisbelievedthat the magnitudeofenergyappliedfavoredtheoccurrenceofthe{176}twininthepolycrystalline uranium.Averagegrainsizeofcasturaniumunderwentasignificantreductionto 92 mm attheendof the process.Theoverallresultsindicatetheshock-loadingapproachasapromisingsteptoward controllingcasturaniumgrainsizeandthusitsmechanicalproperties.


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