Dr. Janaki Ram

8/13/2019 Dr. Janaki Ram

1/34

EmergingTrendsandProspectsin

Dr.G.D.Janaki Ram

MaterialsJoiningLaboratory

DepartmentofMetallurgicalandMaterialsEngineering

n an ns u eo ec no ogy a rasChennai 600036


2/34

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


3/34

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 -


4/34

ASSweld CFBweld


5/34

HighEntropyAlloys

Multi-principalelementalalloys(fourormoreelements)

Simplesolidsolutionsduetohighconfigurational

entropyJWYeh,Taiwan

Since1995

Interestingproperties g strengt

Phasestability

ugg s us v y Excellentoxidation,corrosionandwearresistance


6/34

Several different systemsd di tind diverse propertiesCastingAlCoCrCuFeNi

AlCoCrCuFeMoNiTiVZr

CuCoNiCrAlFeTiV

Mechanical AlloyingAlFeTiCrZnCuNiFeCrCoMnW

CuNiCoZnAlTi

CoCrFeNi

CoCrFeAl

Yeh etal.2004


7/34

XYZ

A B

XAYBZA B

Canthisbedone?


8/34

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)


9/34

Laserdeposition,CrCrFeNi

NiCoCrFe mechanicallyalloyedpowder

Successfullaserdepositiononalloy316LCoCrFeNicoatin

substrates(300W,15mm s)

Soundinterface,nocracking

316Lsubstrate

CoCrFeNipowder CoCrFeNicoating


10/34

TIGwelding,

CoCrNiCuAl


11/34

SS/TiPipeWelding

SiteweldingofSSpipestoTipipesinnuclear

Goodcorrosionresistanceinnitricacid

Fusionweldingisruledout

Solidstateweldingonsiteisimpractical Solidstateweldedjoininginsertcanhelp

SSpipe TipipeSS/Tiinsert

FusionweldFusionweld Solidstateweld


12/34

SS/TiPipeWelding Howtoproducethejoininginsert?

Frictionwelding

Initialexperimentswithpipes,morecomplications

ReasonablygoodweldsbetweenSSandTirods

,

Intermetallicformationcouldnotbeprevented

SS Ti

TiSS


13/34

IN 625

IN625Ti

Ti

SS


14/34

Idea1:Resistancebuttwelding

an ro sw anw ou n er ayer

Sparkplasmasinteringmachine(850C/10kN/2minutes)

,

SSTi

IN625 Ti


15/34

SS/TiPipeWelding

Idea2100Ti

75Ti+25SS

Compositionallygradedinsert

50SS+50Ti

725Ti+75SS

100SS

SSandTipowders

Sparkplasmasintering

Compositiona gra ation

Continuousintermetallic

la er can be avoided

SmootherchangeinCTE

SPSsetupforpowderconsolidation


16/34

SS/TiPipeWelding

100%Ti100%SS

(c)(b)(a)

Ti

SS

Ti

SS

Ti SS

MicrostructuresofacompositionallygradedSS/Tijoininginsert(800C,5minutes,25kN)


17/34

25SS/75Ti

Ti


18/34

SS/TiPipeWelding

Combinesolidstatebondingwiththreading

Sparkplasmasinteringmachine(800C,15kN,5minutes)30

SS

15

30Ti

SS

SS

21

Ti

Ti

SS/TithreadedpipejointafterSPSbondingandmachining

TiSS

SS/TithreadedpipejointafterSPSbondingandmachining

AfterfusionweldingSSandTipipe

extensionstotheinsert


19/34

AdditiveManufacturin Mostprocessesinvolvefusion

Solidificationcracking

Crackinginsolidstate(brittlemicrostructure+

residualstresses)

MetallurgicalincompatibilityAscastmicrostructure(segregation)


20/34

SolidStateProcessesforMaterialAddition

Ultrasonicwelding(UC/UAM)

Othercandidateprocesses:

,

welding,frictionsurfacing Ourfocus:Frictiondeposition

Approach1:Layerwise

1a:withtranslation

1b:withouttranslation Approach2:Linewise

Multipleoverlappingtracks

makeupalayer

oun ntertrac on ng CNCmachiningforlayershaping


21/34


22/34

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.


23/34

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


24/34

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)


25/34

Microstructures

Consumablerod Frictiondeposit

Peaktemperatureduringfrictiondeposition:11201130C(noboridemeltingorcoarsening)

Frictiondeposition(i)Finegrainsize(dynamicrecrystallization),(ii)Fineborideparticlesand

uniformdistribution(plasticdeformation,fragmentation,redistribution)


26/34

Layerswithinalayer

Pro ressivematerialtransferindiscretela ers

Edgeofafrictiondepositedsample

Rotationalplanekeepsmoving

Processterminationinvolvesshearattherotationalplane

Initialheatingduetofriction,thenadiabaticheatingduetosevereplasticdeformation


27/34

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)


28/34

Inconel 718,friction

epos s


29/34

Inconel 718,

frictiondeposits

Asdeposited

Afterdirectaging


30/34

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


31/34

AlCualloyAA2014,frictiondeposits

ProcessparametersFriction force:8kN

Spindlerotationspeed:800rpm

Traversespeed:1mm/s


32/34

Microstructural Characterization

Consumable rod

Friction surfaced deposit


33/34

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


34/34

Dr. Janaki Ram

Documents