Surface enhancement technologies such as shot peening, laser shock peening, and low plasticity burnishing (LPB) can provide substantial fatigue life improvement. However, to be effective, the compressive residual stresses that increase fatigue strength must be retained in service. For successful integration into turbine design, the process must be affordable and compatible with the manufacturing environment. LPB provides thermally stable compression of comparable magnitude and even greater depth than other methods, and can be performed in conventional machine shop environments on CNC machine tools. LPB provides a means to extend the fatigue lives of both new and legacy aircraft engines and ground-based turbines. Improving fatigue performance by introducing deep stable layers of compressive residual stress avoids the generally cost prohibitive alternative of modifying either material or design. The x-ray diffraction based background studies of thermal and mechanical stability of surface enhancement techniques are briefly reviewed, demonstrating the importance of minimizing cold work. The LPB process, tooling, and control systems are described. An overview of current research programs conducted for engine OEMs and the military to apply LPB to a variety of engine and aging aircraft components are presented. Fatigue performance and residual stress data developed to date for several case studies are presented including the following. (1) The effect of LPB on the fatigue performance of the nickel based super alloy IN718, showing the fatigue benefit of thermal stability at engine temperatures. (2) An order of magnitude improvement in damage tolerance of LPB processed Ti-6-4 fan blade leading edges. (3) Elimination of the fretting fatigue debit for Ti-6-4 with prior LPB. (4) Corrosion fatigue mitigation with LPB in Carpenter 450 steel. (5) Damage tolerance improvement in 17-4 PH steel. Where appropriate, the performance of LPB is compared to conventional shot peening after exposure to engine operating temperatures.

Issue Section:
Gas Turbines: Structures and Dynamics
Keywords:
gas turbines, aerospace engines, X-ray diffraction, fatigue testing, thermal stresses, computerised numerical control, tolerance analysis, burnishing, corrosion fatigue, corrosion testing, nickel alloys
Topics:
Compression, Corrosion, Damage, Fatigue, Gas turbines, High cycle fatigue, Plasticity, Stress, X-ray diffraction, Blades, Fatigue strength, Fatigue life, Shot peening, Temperature, Alloys, Fatigue testing
1.
U.S. Patents 5,826,453 (October 1998), 6,415,486 B1 (Jul. 2002) other US and foreign patents pending.
2.
2002, “Low Plasticity Burnishing,” NASA Tech Briefs, Aug., 50 p.
3.
Hogan, B., ed., 2001, “Longer Life With Low-Plasticity Burnishing,” Manufacturing Engineering, SME, pp. 34–38.
4.
Gabb, T., Telesman, J., Kantzos, P., and Preve´y, P., 2002, “Surface Enhancement of Metallic Materials,” Advanced Materials & Processes, ASM, ed., Peg Hunt, Jan., pp. 69–72.
5.
Preve´y, P., 2000, “The Effect of Cold Work on the Thermal Stability of Residual Compression in Surface Enhanced IN718,” Proc. 20th ASM Materials Solutions Conf., St. Louis, MO, Oct. 10–12.
6.
Preve´y, P. et al., 2000, “FOD Resistance and Fatigue Crack Arrest in Low Plasticity Burnished IN718,” Proc. 5th National HCF Conf.
7.
Preve´y, P. et al., 2001, “The Effect of Low Plasticity Burnishing on the HCF Performance and FOD Resistance of Ti-6Al-4V,” Proc. 6th Natl. Turbine Engine HCF Conf., Jacksonville, FL, March 5–8.
8.
Belozerov
,
V. V.
,
Makhatilova
,
A. I.
,
Turovskii
,
M. L.
, and
Shifrin
,
I. M.
,
1986
, “
Increasing the Fatigue Resistance of High-Strength Steel Using Bulk and Surface Treatments
,”
Met. Sci. Heat Treat.
,
28
(
7-8
), pp.
565
–
569
.
9.
Stepurenko
,
V. T.
et al.,
1976
,
Prot. Met.
,
12
, pp.
386
–
389
.
10.
Papshev
,
D. D.
, and
Golubev
,
Yu G.
,
1972
, “
Effectiveness of Surface Work-Hardening of Titanium Alloy Components
,”
Russ. Eng. J.
,
52
(
4
), pp.
48
–
51
.
11.
Freid
,
M. Kh.
et al.,
1994
,
Prot. Met.
,
20
, pp.
263
–
265
.
12.
Belkin
,
L. M.
et al.,
1984
, “
Surface Strengthening of Plane Parts by Plastic Deformation
,”
Sov. Eng. Res.
,
4
(
9
), pp.
30
–
32
.
13.
Belkin
,
L. M.
,
1983
, “
Survivability of Flat Parts Strengthened by Surface Plastic Deformation
,”
Sov. Mater. Sci.
,
19
(
3
), pp.
225
–
228
.
14.
Fattouh
,
M.
et al.,
1988
,
Wear
,
127
, pp.
123
–
137
.
15.
Loh
,
N. H.
et al.,
1989
,
Wear
,
129
, pp.
235
–
243
.
16.
Loh
,
N. H.
et al.,
1993
,
Precis. Eng.
,
15
, pp.
100
–
105
.
17.
Kotiveerachari
,
B.
, and
Murty
,
R. L.
,
1985
,
Int. J. Prod. Res.
,
23
, pp.
499
–
521
.
18.
Hills, D. A. et al., 1979, Proc. Int. Conference Wear of Materials, ASME, New York, NY, pp. 396–402.
19.
Braham, S., and Frelat, J., 1993, Proc. Computer Methods and Exp. Meas. for Surface Treatment Effects, Computational Mechanics, Southampton, UK, pp. 255–264.
20.
Zinn
,
W.
, and
Scholtes
,
B.
,
1999
, “
Mechanical Surface Treatments of Lightweight Materials—Effects on Fatigue Strength and Near-Surface Microstructures
,”
J. Mater. Eng. Perform.
,
8
, pp.
145
–
151
.
21.
Altenberger
,
I.
et al.,
1999
, “
Cyclic Deformation and Near Surface Microstructures of Shot Peened or Deep Rolled Austenitic Stainless Steel AISI 304
,”
Mater. Sci. Eng., A
,
264
, pp.
1
–
16
.
22.
Drechsler
,
A.
et al.,
1998
, “
Mechanical Surface Treatments of Ti-10V-2Fe-3Al for Improved Fatigue Resistance
,”
Mater. Sci. Eng., A
,
243
, pp.
217
–
220
.
23.
Hilley, M. E., ed., 1971, Residual Stress Measurement by X-Ray Diffraction, SAE J784a, Society of Auto. Eng., Warrendale, PA.
24.
Noyan, I. C., and Cohen, J. B., 1987, Residual Stress Measurement by Diffraction and Interpretation, Springer, New York.
25.
Cullity, B. D., 1978, Elements of X-ray Diffraction, 2nd ed., Addison-Wesley Reading, MA, pp. 447–476.
26.
Preve´y, P. S., 1986, “X-Ray Diffraction Residual Stress Techniques,” Metals Handbook, ASME, Metals Park, OH, Vol. 10, pp. 380–392.
27.
Koistinen
,
D. P.
, and
Marburger
,
R. E.
,
1964
,
Trans. ASM
,
67
, p.
67
67
.
28.
Moore
,
M. G.
, and
Evans
,
W. P.
,
1958
, “
Mathematical Correction for Stress in Removed Layers in X-Ray Diffraction Residual Stress Analysis
,”
SAE Trans.
,
66
, pp.
340
–
345
.
29.
Preve´y, P. S., 1977, “A Method of Determining Elastic Properties of Alloys in Selected Crystallographic Directions for X-Ray Diffraction Residual Stress Measurement,” Advances in X-Ray Analysis, Plenum, New York, 1977, Vol. 20, pp. 345–354.
30.
Preve´y, P. S., 1986, “The Use of Pearson VII Functions in X-Ray Diffraction Residual Stress Measurement,” Advances in X-Ray Analysis, Plenum, New York, Vol. 29, pp. 103–112.
31.
Preve´y, P. S., 1987, “The Measurement of Residual Stress and Cold Work Distributions in Nickel Base Alloys,” Residual Stress in Design, Process and Material Selection, ASM, Metals Park, OH.
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