Rohde, M.

Schneider, J.

Südmeyer, I.

KITopen

I ti ti th l h i l d t ib l i lnves ga ons on erma , mec an ca  an  r o og ca  properties of ceramic/steel-jointsI. Südmeyer, J. Schneider, M. RohdeKarlsruhe Institute of Technology, Institute for Applied Materialsmotivationmaterial propertiesltresu smicroscopic compound analysisshear testingtribological testingconclusionKIT – University of the State of Baden-Wuerttemberg and National Laboratory of the Helmholtz Association www.kit.eduMotivationdry running clutch systemTribological application Laser brazingprocess arrangementMechanical characterisationshear strength   pyrometerpressing CO2-laser beamλ = 10,64 µm  clampingFtempered plungerplatesteelbrazeFIPEK, KIT – Campus Southargon ceramicinsulationceramic steelbrazeIAM-AWP, KIT – Campus NorthPShear strengthpin-on-disc experimentprocess conditionslaser output beam Argon stream ≥ 400 Nl/hPF: Fracture loadR: sample radiusτ = Fπ · R²FNv    pressure p ≥ 2 MPatemperature  measurement  τ: fracture stressm: Weibull modulus mIAM - ZBS, KIT – Campus South2 21.06.2011 introduction - brazing results - tribological results - conclusionsMaterial properties                                MaterialProperties Al2O3 PLS-SiC Steel Incusil-brazeSn5050Sn48Ag2TiCompany Friatec AG ESK Ceramics- Morgan Chem. KIT, IMF IDensity ρ / g/cm³ 3.9-3.95 3.0 7.85 9.7 8.3Strength σ / MPa 3501 400 560-710 338 -Youngs modulus / GPa 380 410 210 76 68Thermal conductivity λ, W/mK 38 145 44 166 -Coefficient of thermalexpansion α 10-6 m/K8.4 4.1 11.0 18.2 -Al2O3 steelPLS-SiC ,  20 µm 20 µm20 µm3 21.06.2011 introduction - brazing results - tribological results - conclusionsSEM-images of ceramic/AgCuTi/steel-jointsAl2O3 / AgCuTi / steelSiC-AgCuTi-steelsteelAgCuInTiTi i hAgCuInTi-r creaction layerAl2O3 30 µm Al O3 10 µm2i h tti f A C Ti d A C I Ti b i fill SiCn omogeneous or  no we ng or  g u - an   g u n - raz ng er on   despite a explicit Ti rich reaction zonehomogenous seamless wetting and Ti reach reaction zone on Al O,    -     2 3with AgCuTi- and AgCuInTi-filler4 21.06.2011 introduction - brazing results - tribological results - conclusionsSEM images of SiC-steel joints50Sn48Ag2TiSiC-AgCuTi-steelSteel Sn,Ag eutecticumS  utectic phase50Sn48Ag2Ti 10 µmSiC 100 µmTi rich reaction zone10 µmgood seamless wetting for SnAgTi-alloys with Sn ≥ 30wt% above T ≥ 900°Cthin, inhomogeneous Ti rich reaction zonelarge Ti-particles in inner braze region5 21.06.2011 introduction - brazing results - tribological results - conclusionsThermal resistance of ceramic-steel joints1. 2. 3.measuring principle of LFA thermal diffusivity and thermal resistance of brazed joints0 240.28m²/s]1.82.0SiC-AgCuTi-steelSiC-SnAgTi-steelAl2O3-AgCuTi-steel cm²K/W]measuring of  T = f(t) α(T)λ = α · cP · ρ 0.160.20.sivity [cm1.41.6nce Rth [ccalculation of Rth 0.080.12rmal diffus0 041.2al resistansjointλjointsceramidλceramic=ssteelλsteelsinterfaceλinterface+ + 0 200 400 6000.000.04ther0.00.thermaRthtemperature / °C6 21.06.2011 introduction - brazing results - tribological results - conclusionsShear strength of laser brazed Al2O3/AgCuInTi/steel-joints2 laser output beam:F1   non structured: τ0 = 21 MPa, m = 5,1h i d l b1-F)))0omogen ze  aser eam: non structured: τ0 = 26 MPa, m = 2,0 structured steel: τ0 = 42 MPa, m = 2,1ln(ln(1/(1-2-1obability -3cture proensity 2 ] nsity 2 ]homogenizing optic1 2 3 4 5-4fracflaser inte[W/m2laser inen[W/m2racture shear stress lnτBLASERlensehomogenizer7 21.06.2011 introduction - brazing results - tribological results - conclusionsShear strength of laser brazed Al2O3/AgCuInTi/steel-joints2 laser output beam:1   non structured: τ0 = 21 MPa, m = 5,1h i d l b1-F)))F0omogen ze  aser eam: non structured: τ0 = 26 MPa, m = 2,0 structured steel: τ0 = 42 MPa, m = 2,1ln(ln(1/(1-2-1obability homogenizing optic-3cture prointensity W/m2 ]inensity W/m2 ] fracture surface1 2 3 4 5-4fracflaser [Wlaser [W1 mm 1 mmracture shear stress lnτB LASERlensehomogenizerhomogeneous wetting fracture of ceramic8 21.06.2011 introduction - brazing results - tribological results - conclusionsShear tests of laser brazed SiC-SnAgTi-steel jointsvariation laser beam profile2F))laser output beam  structured SiC: τ0 = 24 MPa, m = 5.5FτBruch ≥ 5 01nln(1/(1- non structured: τ0= 19 MPa, m = 4.9 structured steel:τ0 = 20 MPa, m = 3.1-1bability / l homogenized laser output beam structured steel:τ0 = 34 MPa, m = 12.7Keramikbruch in Bereichen mit Reaktionsschicht-3-2ture probτBruch ≤ 15 MPa1.6 2.4 3.2 4.0-4fract  frature shear stress ln τB1 mmKeine Reaktionsschicht Bruch in der Grenzfläche9 21.06.2011 introduction - brazing results - tribological results - conclusions           Tribological testingv disc steel AISI 1045 (normalised), 206 HV30pin Al O : monolithic brazed8 mmFN2 3  , PLS-SiC : monolithic, brazedtesting samplesF = 100 N (2 MPa)N     air, rel. hum.50%/ NN/ N50 cycles (≙ 6300 m)- loading- 5 s ramp al load FNvelocity FN- 5 s holding- 5 s slow downl dinormasliding v- un oa ng- 5 s pause- ... testing time t / s10 21.06.2011     introduction - brazing results - tribological results - conclusionsTribological characterisation of Al2O3 and PLS-SiC0,80,8Al2O3 / steel PLS-SiC / steel0,10000,20000,30000,40000,60,70,60,70,50000,60000,70000,40,5ficient µ0,40,5cient µ0,80000,20,3Friction Coef0,20,3Friction Coeffi24680,1150180210240270300T °CSliding Sp24680,1150180210240270300T °CSliding S1012 6090120Temperature , eed v, m/s1012 6090120Temperature ,  peed v, m/sPLS-SiC exhibits compared to Al2O3 a higher friction coefficient      , a lower and more constant friction gradient andthe highest temperatures.11 21.06.2011 introduction - brazing results - tribological results - conclusionsTribological characterisation average friction coefficient µ average temperatureTAl2O3/steel-joints0,5erage   average  average300°C0 30,4efficient µave200250ure T average, 0,2,riction Coe Al2O3 (99,7), monolith 100150Temperatu Al2O3 (99,7), monolith0 00,1Average F  Al2O3 (99,7), laser brazed, 2 mm Al2O3 (99,7), laser brazed, 4 mm Al2O3 (99,7), glued, 4 mm 050Average Al2O3 (99,7), laser brazed, 2 mm Al2O3 (99,7), laser brazed, 4 mm Al2O3 (99,7), glued, 4 mm0 5 10 15 20 25 30 35 40 45 50,Loading Cycle0 5 10 15 20 25 30 35 40 45 50Loading CycleAl2O3-joints exhibit higher average friction coefficients than the Al2O3-monolith.only few differences of average temperature between monolith and joint12 21.06.2011 introduction - brazing results - tribological results - conclusionsTribological characterisationAl2O3/steel-jointsfriction gradient dµ/dv0 00 Al O (99 7) monolith-0,01,µ/dv2 3 ,   Al2O3 (99,7), laser brazed, 2 mm Al2O3 (99,7), laser brazed, 4 mmAl O (99 7) gl ed 4 mm-0,02Gradient dµ2 3 , , u ,  -0,04-0,03Friction G5 10 15 20 25 30 35 40 45 50-0,05Al2O3-monolith exhibits the lowest friction gradient dµ/dv compared to Loading Cycle13 21.06.2011Al2O3-brazing joints.  introduction - brazing results - tribological results - conclusionsTribological characterisationPLS-SiC/steel-joints: variation of joining technique0 80 80,7,gePLS-SiCerage.0.70 50,6cient µaveraglued steel bushscrewcient µave0.60 50,4,on Coefficclampedon coeffic .0.40 20,3rage Fricti V14V15laser brazedage frictio0.30 20,1,Aver  V16 V17 MittelAvera .0.10 10 20 30 40 500,0Loading CycleLoading Cycle0 10 20 30 40 5014 21.06.2011 introduction - brazing results - tribological results - conclusions Tribological characterisationPLS-SiC/steel-joints: variation of joining technique0 010,00v001250300laserclamped30250°C-0,02- ,ient dµ/dv laser brazedclampedent dµ/dv -.-.02200T average, °C brazed20T average/ -0,03Friction Gradi V14V15gluedion gradie-.03100150Temperature T V14V15 V26 V27 3536glued150100perature -0,05-0,04  V16 V17 MittelFricti-. 4-. 5 050T   V16 V17 Mittel V28 V29 Mittel  37500Temp0 10 20 30 40 50Loading CycleLoading Cycle0 10 20 30 40 50 0 10 20 30 40 50Loading CycleLoading Cycle0 10 20 30 40 5015 21.06.2011 introduction - brazing results - tribological results - conclusionsTribological characterisation0,10000 2000PLS-SiC/steel-joints0,8laser brazed0,8glued0,8clamped,0,30000,40000,50000,60,70,60,70,60,7 0,60000,70000,80000,40,5Coefficient µ0,40,5oefficient µ0,40,5oefficient µ0,20,3Friction 0,20,3Friction C0,20,3Friction C246810120,16090120150180210240270300Temperature T, °CSliding Speed v, m246810120,16090120150180210240270300mperature T, °CSliding Speed v, m246810120,16090120150180210240270300Temperature T, °CSliding Speed v, m/  /s Te /ss16 21.06.2011 introduction - brazing results - tribological results - conclusionssummaryBrazing resultsno reproducable wetting of SiC with AgCuTi filler      -good wetting of SiC was only achieved with SnAgTi-fillers for Sn fraction ≥ 30wt%b i h Ti i h i lut n omogeneous -r c  react on ayerincrease of compound strength of ceramic/steel joints with homogenizing opticAl2O3/AgCuInTi/steel-joints: from 20 MPa (m = 5) to 42 MPa (m = 2) Tribological res lts uSiC shows a higher and more constant friction coefficient than Al2O3higher temperatures of 250°Cinfluence of joining technique on tribological behaviour17 21.06.2011 introduction - brazing results - tribological results - conclusionsTh k f tt ti !an  you or your a en onThe authors thank the Deutsche Forschungsgemeinschaft for suppporting the S d f h b i h 483 Hi h f lidion er orsc ungs ere c   „ g  per ormance s ng and friction systems on the basis of engineering ceramics“.18 21.06.2011

Investigations on thermal, mechanical and tribological properties of ceramic/steel joints

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