irradiation segregation and boundary characteristics

8/18/2019 Irradiation Segregation and Boundary Characteristics

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Radiation InducedSegregation

Arun Babu

Aabhash Agrawal

IIT KGP


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Radiation• Emission or transmission of energy in the form o

waes or !articles through s!ace or through amaterial"

• #eutrons$ ions$ electrons and gamma rays"

• All of these forms of radiation hae the ca!abilityto dis!lace atoms from their lattice sites$ which ithe fundamental !rocess that dries the changesin structural metals"


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Irradiation• It is the !rocess by which an ob%ect is e&!osed

to radiation"

• S!atial redistribution of solute and im!urityelements in the metal"

• !roduces point defects and defect clusterswith an a!!ro&imately random distributionthroughout the material"

• These defects are mobile and attracted to

dislocations$ grain boundaries and other defecsin's"


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Radiation InducedSegregation• (ormation of mobile defects) attracted to sin's) such

dislocations or GBS"

• di*erent atomic s!ecies in an alloy moe at di*erent

rates in res!onse to these !oint)defect +u&es ) somes!ecies moe towards sin's while others moe away"

• inerse 'ir'endall e*ect


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• ,auses signi-cant changes in the local com!ositionnear sin's such as grain boundaries

• im!lications for the bul' !ro!erties of materials"

• RIS leads to chromium de!letion in GBSs"

• Radiation assisted stress corrosion crac'ing in

austenitic face

.// series stainless steel irradiated at 0 1PI2


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RIS

4" 5iao$ 6/77$ austenitic stainlesssteels


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Parameters a*ecting RIS

• 8acancy formation energy) 9ess RIS for more energy) Threse&ists for RIS below which RIS constant

• 8acancy segregation energy) di*erence between the formatat a GB site and in the bul'" The higher segregation energy acancy formation energy"


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• Introduction of coherent twins into a microstructure

•

method to su!!ress deleterious ,r segregation• but does not !roide ade


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•?. coherent twin)a high formationenergy and ery lowmagnitude for RIS"

• ?. incoherent twin and the 70@ GB hadsimilar acancy formations energies$/"/ e8 and /"6 e8$ res!ectiely$ ande&hibited similar ,r de!letion"

• ?C GB the formation energy was muchlower D/"60 e8)e


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T"S" 1uh et al"$ 6///$ !roton)irradiated ./> stainless steel

K"G" (ield model ferr


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References

• ,hristo!her =" Barr$ Gregory A" 8etteric'$ Kinga A" Hnocic$ Khalid attar$ Jian)=ing B

Acta =aterialia 0C D6/7> 7>:7

• Selby$ Aaron Patric'$ L=odeling Radiation)Induced Segregation in (erritic)=artensitic Thesis$ Hniersity of Tennessee$ 6/7

• Kein G" (ield$ 9eland =" Barnard$ ,had =" Parish$ 5eremy T" Busby$ 1ane =organ$ Tod#uclear =aterials >. D6/7. 7C6:7/

• T"S" 1uh$ 5"5" Kai$ ("R" ,hen$ 5ournal of #uclear =aterials 6.)6C D6/// 7)6/>

•

4" 5iao$ G"S" Nas$ Acta =aterialia D6/77 766/:76.• K"G" (ield$9eland =" Barnard$ ,had =" Parish$5eremy T" Busby$ 1ane =organ$Todd R" A

5ournal of #uclear =aterials >. D6/7. 7C6:7/

• T"S" 1uh$ 5K Kai$ (R ,hen$ 9 Nang$ $ 5ournal of #uclear =aterials 6> D6//7 60C)6C

• ,hristo!her =" Barr$Gregory A" 8etteric'$ Kinga A" Hnocic$ Khalid attar$ Jian)=ing BaActa =aterialia 0C D6/7> 7>:7


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Than' Oou

irradiation segregation and boundary characteristics

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