Keith Legg 847-680-9420

Summary of coating integrity and planned testing

HCAT Program ReviewAugust 2001

Toronto

Keith Legg 847-680-9420

Big bar tests at NAWC, PAX River

#6, R= -1, WC-Co 0.012”

Failed at 180 ksi

#2, R= -0.33, WC-Co 0.012”

Test 1 180 ksi 20 cycle

Failed at 200 ksi

R= -1, WC-Co 0.003” Passed 220 ksi

#6

#2

Very sensitive to thickness.Insensitive to R

Very sensitive to thickness.Insensitive to R

Big bars not much different to small

Big bars not much different to small

Keith Legg 847-680-9420

Hill AFB re-optimization

WC-Co looks good to 240 ksi, R=-0.5

Note failures at higher substrate T, lower dep rate

Ctg Matl ThicknessPyrom T Dep rate R-ratio No Spall ksi Spall ksiWC-Co 0.005 220-230 -1.0 220WC-Co 0.005 220-230 -1.0 190WC-Co 0.015 220-230 -0.33 170 190WC-Co 0.005 165-175 -0.5 240WC-CoCr 0.010 165-175 0.5 0.1 220WC-Co 0.005 165-175 0.5 -1.0 190WC-Co 0.015 165-175 0.5 -0.5 190WC-Co 0.005 165-175 0.5 -0.33 190WC-CoCr 0.005 165-175 0.5 0.1 190WC-CoCr 0.005 165-175 0.5 -1.0 180WC-Co 0.005 165-175 0.5 0.1 180WC-Co 0.015 165-175 0.5 0.1 180WC-CoCr 0.005 165-175 0.5 -1.0 180WC-Co 0.015 165-175 0.5 -0.5 240WC-Co 0.005 ??? 0.2 -0.5 240WC-Co 0.015 ??? 0.25 -0.5 180

Spalling Data

0

50

100

150

200

250

300

-1.1 -1.0 -0.9 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2

R-ratio

Ma

x s

tre

ss

, k

si

No Spall ksi

Spall ksi

WC-CoCr

WC-Co, 3 ptsWC-Co fail

We can make 0.005”, 0.015” WC-Co coatings that do not spall at 240 ksi, R=-0.5

Keith Legg 847-680-9420

Latest data from 40 specimens coated at Southwest Aero, 0.003”, 100 cycles at each load to 240 ksi

Smax @

R=-0.5

M5-7, WC-CoCr full M5-17, WC-CoCr patch

M5-28, WC-Co patch

M5-37, WC-Co full

190 Subsurface* Subsurface None None

200 Crack @ 51 cycles Subsurface None Subsurface & bulging**

210 Crack, no spalling Crack @ 60 cycles Crack @ 85 cycles, some subsurface

Same

220 Crack, no spalling Crack, no spalling Crack, no spalling Same

230 Crack, no spalling Crack, no spalling Crack, some bulging**

Same

240 Nf=3046 cycles, spalling @ fracture

Nf=3004 cycles, spalling @ fracture

Nf=3368 cycles, spalling

Crack @ 72 cycles, Nf=3716 cycles

WC-CoCr survived to 240 ksi and exceed NfDoes this mean WC-CoCr is not a lot more brittle than WC-Co?

WC-CoCr survived to 240 ksi and exceed NfDoes this mean WC-CoCr is not a lot more brittle than WC-Co?

Keith Legg 847-680-9420

Ogden ALC A-10 LG bend tests, R=-0.33

0.010” WC-Co deposited at OO-ALC using new parameters 500 cycles at loads to 190 ksi ultrasonic tests showed no delamination 50 cycles at loads >190 ksi no spalling at 240 ksi (yield) coating spalled at 256 ksi (>yield)

0.015” WC-Co spalled at low load - cause unknown

We can reach 240 ksi with thick coatingIs spalling very sensitive to thickness?

We can reach 240 ksi with thick coatingIs spalling very sensitive to thickness?

Keith Legg 847-680-9420

Conclusions to date

WC-Co and WC-CoCr can both exceed commercial requirements for OEM coatings (0.003”)

WC-Co can exceed Air Force (land-based aircraft) requirements for rebuild coatings

Spalling appears most sensitive to deposition conditions (how it is optimized) coating thickness

Spalling appears not very sensitive to sample diameter (details of coating morphology) R ratio (once you get interface cracking it does not

need a big push to delaminate)WC-Co looking likely to work for all but high-bend parts

Keith Legg 847-680-9420

Work to be done

Additional testing Additional samples and big bar tests at NAWC New samples and big bar tests at Metcut and AFRL Bend tests to examine D/T ratios at Hill Additional A-10 bend tests at Hill Bending fatigue of large cylinders at Goodrich

Process mapping Coatings can exceed requirements - let’s make sure we

know how to ensure they always do! Consideration of rebuild options

Ensure coating integrity through deposition control Duplex coatings (alloy build-up, carbide cap)

e.g. Long Beach Joe Kolek reported Tribaloy does not crack - is it a good rebuild, or is NiAl better (cc sulfamate Ni)?