dr. janaki ram
TRANSCRIPT
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EmergingTrendsandProspectsin
Dr.G.D.Janaki Ram
MaterialsJoiningLaboratory
DepartmentofMetallurgicalandMaterialsEngineering
n an ns u eo ec no ogy a rasChennai 600036
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Carbidefreebainite welds
Element
Composition (wt.%)
Base metal Weld metal
C 0.3 0.28
n . .
Si 0.6 1.55Cr 0.8 1.20
Ni - 0.95
o . .
Co - 2.05
S 0.15 0.003
P 0.15 0.013
CFBweldmetal
Preheat:350C200
300
Postheat:350C/8h
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Carbidefree bainite welds
amp e a onga on oca on o a ure
CFB weld 1110 12 Weld metal
HAZus en c we
Base material 1200 10 -
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ASSweld CFBweld
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HighEntropyAlloys
Multi-principalelementalalloys(fourormoreelements)
Simplesolidsolutionsduetohighconfigurational
entropyJWYeh,Taiwan
Since1995
Interestingproperties g strengt
Phasestability
ugg s us v y Excellentoxidation,corrosionandwearresistance
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Several different systemsd di tind diverse propertiesCastingAlCoCrCuFeNi
AlCoCrCuFeMoNiTiVZr
CuCoNiCrAlFeTiV
Mechanical AlloyingAlFeTiCrZnCuNiFeCrCoMnW
CuNiCoZnAlTi
CoCrFeNi
CoCrFeAl
Yeh etal.2004
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XYZ
A B
XAYBZA B
Canthisbedone?
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HEAcoatings
Increasing interest in HEAs as coating materials
Laser cladding
r coa ngs on - - uang e a . ur ace an
Coatings technology, 2011)
FeCoNiCrAl2Si coatings on low carbon steel (Zhang et al.
Intermetallics, 2011)
FeCoNiCrCu coatings on low carbon steel (Zhang et al.,
Plasma spray
NiCoFeCrSiAlTi coatings on austenitic stainless steel 304
(Wang et al., Materials Chemistry and Physics, 2011) Magnetron sputtering
.,
and Coatings technology, 2007)
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Laserdeposition,CrCrFeNi
NiCoCrFe mechanicallyalloyedpowder
Successfullaserdepositiononalloy316LCoCrFeNicoatin
substrates(300W,15mm s)
Soundinterface,nocracking
316Lsubstrate
CoCrFeNipowder CoCrFeNicoating
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TIGwelding,
CoCrNiCuAl
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SS/TiPipeWelding
SiteweldingofSSpipestoTipipesinnuclear
Goodcorrosionresistanceinnitricacid
Fusionweldingisruledout
Solidstateweldingonsiteisimpractical Solidstateweldedjoininginsertcanhelp
SSpipe TipipeSS/Tiinsert
FusionweldFusionweld Solidstateweld
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SS/TiPipeWelding Howtoproducethejoininginsert?
Frictionwelding
Initialexperimentswithpipes,morecomplications
ReasonablygoodweldsbetweenSSandTirods
,
Intermetallicformationcouldnotbeprevented
SS Ti
TiSS
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IN 625
IN625Ti
Ti
SS
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Idea1:Resistancebuttwelding
an ro sw anw ou n er ayer
Sparkplasmasinteringmachine(850C/10kN/2minutes)
,
SSTi
IN625 Ti
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SS/TiPipeWelding
Idea2100Ti
75Ti+25SS
Compositionallygradedinsert
50SS+50Ti
725Ti+75SS
100SS
SSandTipowders
Sparkplasmasintering
Compositiona gra ation
Continuousintermetallic
la er can be avoided
SmootherchangeinCTE
SPSsetupforpowderconsolidation
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SS/TiPipeWelding
100%Ti100%SS
(c)(b)(a)
Ti
SS
Ti
SS
Ti SS
MicrostructuresofacompositionallygradedSS/Tijoininginsert(800C,5minutes,25kN)
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25SS/75Ti
Ti
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SS/TiPipeWelding
Combinesolidstatebondingwiththreading
Sparkplasmasinteringmachine(800C,15kN,5minutes)30
SS
15
30Ti
SS
SS
21
Ti
Ti
SS/TithreadedpipejointafterSPSbondingandmachining
TiSS
SS/TithreadedpipejointafterSPSbondingandmachining
AfterfusionweldingSSandTipipe
extensionstotheinsert
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AdditiveManufacturin Mostprocessesinvolvefusion
Solidificationcracking
Crackinginsolidstate(brittlemicrostructure+
residualstresses)
MetallurgicalincompatibilityAscastmicrostructure(segregation)
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SolidStateProcessesforMaterialAddition
Ultrasonicwelding(UC/UAM)
Othercandidateprocesses:
,
welding,frictionsurfacing Ourfocus:Frictiondeposition
Approach1:Layerwise
1a:withtranslation
1b:withouttranslation Approach2:Linewise
Multipleoverlappingtracks
makeupalayer
oun ntertrac on ng CNCmachiningforlayershaping
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BoratedStainlessSteels304B7GradeA
Deve ope orneutrons e ngpurposes.
contentandboridemorphology. ASTMA887coverseight
differenttypes 0.2to2.25wt%.
boron);GradeAandGradeBin
eachtype.
GradeAmaterials(PMroute)
showfine,uniformlydistributed
or es e er uc yan toughnessthanGradeB
materials.
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Weldability Attractivemechanicalproperties,butpoorfusion
weldability
Solidificationendwithaeutecticreaction:
L +boride
Widesolidificationrange
Interdendritic eutecticnetwork(poorductilityandtoughness)
Excellentboridestability
Fusionzonemicrostructure,304B4TIGweld1075C/4h 1125C/4h
1175C/4h 1225C/4h
304B4,DSCscan(onheating)Microstructuresafterisothermaltreatments
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FrictiondepositionofASTM304B4GradeB Cylindricalsamplesformicroscopy,tensile,andimpacttests
Consumablerods:10mmdia 304B4GradeBrods(rotatingside)
Substrate:15mmdia AISI304rods(stationaryside)
Parameters:800rpmspindlerotationspeed,8kN frictionforceand1mmburnoff
Composition(wt.%)
C 0.02(0.08)
Cr 18.5 1820
Layerthicknessaftermachining:~0.6mm
Ni 12.5(1215)
B 1.15(11.24)
Mn 1.3(2)
Si 0.5(0.75)
S 0.008(0.03)
P 0.02(0.045)Impactspecimens:5x5x55mm
Fe Balance
Tensilespecimens:10mmgaugelength,3mmgaugewidth,
2mmthickness,40mmtotallength(ASTME8)
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Microstructures
Consumablerod Frictiondeposit
Peaktemperatureduringfrictiondeposition:11201130C(noboridemeltingorcoarsening)
Frictiondeposition(i)Finegrainsize(dynamicrecrystallization),(ii)Fineborideparticlesand
uniformdistribution(plasticdeformation,fragmentation,redistribution)
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Layerswithinalayer
Pro ressivematerialtransferindiscretela ers
Edgeofafrictiondepositedsample
Rotationalplanekeepsmoving
Processterminationinvolvesshearattherotationalplane
Initialheatingduetofriction,thenadiabaticheatingduetosevereplasticdeformation
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Mechanicalproperties
Specimen-
Impact Energy
(5 x 5 mm) (J)
Hardness
(BHN)Yield Strength
(MPa)
Ultimate Tensile
Strength (MPa)
% Elongation
(10 mm GL)
304B4-Grade B bulk material
(specified)205 515 16 - 217
304B4-Grade B bulk material
(obtained)
304B4-Grade B friction deposit 330 700 28 11 230
Bulkmaterial Frictiondeposit Bulkmaterial Frictiondeposit
Tensilefracturesurfaces Impactfracturesurfaces
Frictiondepositionresultedinimproved
strength,ductility,andtoughness(finer
Fractureline
grainsize,finerandmoreuniformly
distributedborides)
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Inconel 718,friction
epos s
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Inconel 718,
frictiondeposits
Asdeposited
Afterdirectaging
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Inconel 718,frictiondepositsProperty Specified Bulk material Frictiondeposits
Tensile
. a
UTS(MPa) 1275 1410 1440
%Elongation 12 22 14
Stressrupture(650C/690MPa)
Rupturelife(hours) 23 >100 2030
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AlCualloyAA2014,frictiondeposits
ProcessparametersFriction force:8kN
Spindlerotationspeed:800rpm
Traversespeed:1mm/s
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Microstructural Characterization
Consumable rod
Friction surfaced deposit
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Hardnessstudies
Frictiondeposit(AD),toplayer:94106HV
Frictiondeposit(AD),bottomlayer:7282HV
Frictiondeposit(DA):8590HV
Frictiondeposit(STA):132138HV
oy : m n mum
STA:485C/1h/WQ+180C/10hAsdeposited
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