Surface Flaw Effect on LCF Life of a Ni-based Superalloy under Shot Peen Conditions ISABE Ross Miller Honeywell Aerospace Phoenix, AZ
|
|
- Agatha McLaughlin
- 5 years ago
- Views:
Transcription
1 Surface Flaw Effect on LCF Life of a Ni-based Superalloy under Shot Peen Conditions ISABE Ross Miller Honeywell Aerospace Phoenix, AZ Abstract Residual stresses are known to influence the fatigue life of components. Shot peening is a post-machining process used to increase fatigue resistance by inducing cold work and compressive residual stresses on the surface and subsurface of the material. Due to the increased compressive residual stresses shot peened specimens have a higher average total low-cycle fatigue (LCF) life than as-machined surfaces, however it is ambiguous as to the effect on low LCF life events. Failures associated with low fatigue life are typically associated with machining anomalies or near surface material defects that cause a severe debit to fatigue life. The intent of this experiment was to evaluate the effect of small surface flaws, introduced prior to shot peen, on total LCF life. shot at the surface while controlling the velocity, distance, size of shot, and time of exposure. Shot peen creates areas of overlapping plastic deformation leaving a dimpled layer that increases cold work (10%-20%) to a depth of and compressive residual stresses to a depth of Figure 1 shows a typical residual stress profile of a peened surface using X-ray diffraction techniques with peak residual stresses being subsurface [1]. Introduction Typical machining methods used for creating features in aerospace hardware have the possibility for inducing anomalies that may act as small flaws reducing the total fatigue life of the component. Special consideration is taken in high stress applications to control the machining parameters in order to minimize the variation in the machined surface. It is typical in these critical pieces of hardware to use component specimens that mimic the geometry, stress and operating temperature to test under low-cycle fatigue (LCF) conditions in order to characterize the fatigue life. For certain applications, it may be of interest to increase the fatigue life or reduce the risk of a component failure by increasing near surface compressive residual stresses by using postmachining surface treatments. One of the most common and economical methods for increasing fatigue resistance is shot peening. Shot peening is completed by spraying high velocity glass or steel Figure 1 - Representative residual stresses of a shot peened surface measured using XRD techniques. However, it has been shown that thermal exposures relax residual stresses induced by post-machining surface treatments and is exceptionally true with shot peened specimens [1]. This is believed to occur due to the increased cold work that is also added to the surface during the shot peen process. In order to fully understand long term effects of small flaws on the notched specimens, thermal relaxation must therefore be taken into consideration. When characterizing LCF life, total life is a combination of cycles to crack initiation and crack propagation cycles. For a given stress state propagation cycles are consistent for as-machined and shot peened surfaces, because the compressive 1
2 residual stresses induced during shot peening are near surface and do not affect the bulk of the component. The benefit of shot peen comes from increasing cycles to crack initiation as LCF mean stress is decreased due to compressive residual stresses. It is the intent of this work to combine the effects of machining-like flaws underneath the shot peened surface in order to characterize the flaw size that may create a debit to total LCF life. Experiment DP-718 is a delta processed version of alloy 718 (more commonly referred to as Inconel 718). This is a Ni-based superalloy used in a variety of aerospace applications including seals, turbines and compressors. The variation of the heat treatment causes the delta phase to become spherical in shape (see figure 2), different from the typical Widmastatten delta that is apparent along the grain boundaries of alloy 718. This allows for increased fatigue life and better tensile properties and refines the grain structure to minimize the variation in the mechanical properties [2]. (approximately 25 hours) then the second step was a cyclic triangular waveform, f=0.333hz, T=1225 F, R- ratio = 0.05, and σ max = 75% of yield strength for 30,000 cycles. After 30,000 cycles the frequency was increased to 3.33Hz until failure. The purpose of the low stress, 90s hold time portion of the fatigue is to represent long term engine usage since thermal exposure at elevated temperatures is known to relax surface residual stresses. This is accentuated in heavily cold worked materials such as those with shot peened surfaces [1][3]. Since cold work is highest at the surface, the residual stresses have completely relaxed after thermal exposure. Less relaxation occurs as cold work decreases internally leading to a peak residual stress at a similar location as the original shot peen condition. As shown in figure 3 both static-no stress and cyclic-stress thermal exposures decrease the residual stresses, but cyclic-stress conditions were applied to the specimens in order to better represent practical engine conditions. The specimen geometry used is a double edge notch as shown in figure 4a, notches were machined using low stress grind, and polished to limit fatigue life variation caused by surface roughness. Figure 3 - Effect of shot peening and thermal exposure on machined specimens. Figure 2 - Typical Kalling s etched microstructure of DP718. The fatigue testing was separated into two steps. The first step was cyclic trapezoidal waveform with 90s hold time at peak stress, T = 1225 F, R-ratio = 0.05, and σ max = 33% of yield strength. The trapezoidal waveform was run for 1000 cycles Figure 4 - Initial specimen geometry (a) followed by the assumed skim cut required to remove the precrack (b). Representative EDM starter flaw (c) and anticipated small flaw geometry (d). 2
3 Specimens were tested in multiple conditions in order to better represent different machining characteristics, as shown in table 1. In order to create the notch defect, an EDM flaw was placed in one of the notches. Specimens were pre-cracked at a nominal peak stress of 50% of yield strength, R- ratio = 0.05 until 2c was approximately 50% larger in length with an assumption that a/c ratio was 1. Using submerged wire-edm the notches were skim cut to remove the starter notch and leave a flaw on the order of while maintaining the original notch radius, see figure 4(d). The recast layer left by the EDM surface was polished off leaving a surface roughness similar to the as-machined condition to maintain consistency. Then the specimen notches were shot peened using consistent parameters covering any remaining flaw. Striations were used to determine the crack propagation cycles by measuring the density of the striations in relation to the distance from the initiation location. By plotting striation density vs crack depth and integrating over the total propagation length (0.015 to overload), crack propagation cycles can be estimated [4]. Using asmachined specimens it was determined that crack propagation cycles were approximately 5,000 cycles of total fatigue life. For striation analysis it was assumed that the initial flaw size was in depth with an a/c ratio = 1. Since is it anticipated that subsurface crack propagation rate is not affected by surface residual stresses, the asmachined striation analysis will be used for shot peened specimens. Test Condition as-machined, 5 100% 100% large precrack large precrack, 6 100% 100% shot peen Small precrack, 12 75% 25% shot peen Table 1 - Specimen testing per each condition and breakdown of failure mode. Results & Discussion # of specimens tested % surface initiation % initiation due to added flaw as-machined 6 0% NA The first evaluation was to determine the fatigue life of the as-machined condition and to understand the failure mechanisms associated with the current component specimens. Average total fatigue life for the as-machined specimens was greater than 150,000 cycles. Initiation site documentation, using a scanning electron microscope (SEM), showed that all of the asmachined specimens had subsurface primary initiations being either a crystallographic facet or Ti/Nb carbides. Average depth of the subsurface initiation location was This depth correlates to the maximum compressive residual stress depth (figure 3). The fracture path showed the majority of the crack propagation to be transgranular in nature allowing for striation analysis to be completed on the specimens. Figure 5 - lognormal probability plot of total cycles to failure for all tested specimens. Specimens tested with a large flaw contained the EDM notch plus the precrack but did not have any portion of the notch or precrack removed nor were these specimens shot peened. These specimens had extremely low fatigue lives, 25% of the propagation life, as the crack began to propagate immediately and at an accelerated crack growth rate due to the large size of the initial flaw and subsequently a high stress intensity factor. During fracture surface analysis, it was determined that these specimens showed an all intergranular crack propagation path correlating to the high stress intensity. A subset of the large flaw specimens were shot peened to determine if there was any benefit or variation in fatigue life. As shown in figure 5, there is an increase in total fatigue life 2x the as-machined, large flaw specimens. However, it is due to a decrease in crack propagation rate from the near 3
4 surface compressive residual stresses from a decrease in the mean stress from surface residual stresses. Propagation still occurred immediately and was 60% of propagation life compared to the asmachined specimens. These flaws are larger than what typically would occur due to machining defects in controlled aerospace applications categorizing them as beyond a worst case scenario and show no benefit from shot peening. Figure 6 shows a typical representation that compares the original EDM notch surface with the remaining flaw for failures lower than the propagation life. The large flaw size had an average depth of which is about half the minimum predicted flaw size to immediately start crack propagation. The flaw size depth ranged from to with little variation in the total cycles to failure all of which were less than the calculated propagation cycles. The final set of specimens had their flaws decreased in size to better represent a machining flaw. These flaws averaged in depth. This set of specimens is broken into two groups, one in which the induced flaw remained after the skim cut removal and the other in which no induced flaw remained. The group which had a flaw remaining can further be separated as represented in both figures 5 and 7. Two specimens still contained large enough flaws to initiate crack propagation immediately and were less than 50% of the propagation cycles, however there were two specimens that 40% of the total life was represented by crack propagation cycles. These two specimens had an initial flaw depth just slightly larger than the peak residual stress. The final two specimens had <2% of total life represented by crack propagation which is on order of the as-machined specimens and shot peened specimens that contained no remaining induced flaw. These final two specimens showed no debit due to the initial flaw size. Specimens not containing the induced flaw showed an average fatigue life of 3x the as-machined specimens and had multiple initiations both surface and subsurface. Surface initiations were assumed to have arrested due to the compressive residual stresses as their initial depth never exceeded the maximum compressive residual stress. Since the surface residual stresses were mostly relaxed it is likely that initiation occurred early since the initiation sites were heavily oxidized. Subsurface initiations were similar to those of the as-machined being either Ti/Nb carbides or faceted in nature. Figure 6 - Overall macro photo representing a large flaw fracture surface. (b) Represents a close-up SEM photo of the precrack surface transitioning into the LCF crack face (separation occurs at the dashed line). (c) An SEM image showing intergranular failure that occurs during cyclic LCF of large flaw initiations 4
5 Conclusions Shot peened specimens do show a benefit in both average and minimum fatigue life when compared to as-machined specimens. In situations where the flaw is large enough, crack propagation occurs immediately with a high crack tip stress, inducing intergranular crack propagation. Since the specimens underwent a thermal exposure prior to fatigue testing, surface residual stresses are near due to the decrease in mean applied stress from the compressive residual stresses near to the crack tip. This is shown in figure 7 by the vertical shift in cycles to failure of the large flaw, shot peen specimens over the as-machined, large flaw specimens even though the initial flaw depths are similar. However, any remaining residual stresses are not significant enough to delay crack initiation since total fatigue life is still less than the 5000 propagation cycles. Figure 7 - Primary initiation depth vs. cycles to failure for all specimens. For subsurface initiations the measure depth is the length of the flaw perpendicular to the notch surface. zero which is more representative of long term engine exposure conditions. Upon viewing figure 7, a flaw can be considered small when it is less than the depth of the peak compressive residual stress, otherwise it will be considered large. This also correlates with the as-machined specimens, since the peak residual stress is similar in location to the depth of primary initiation. However, the notches in this study were machined in order to keep residual stresses near zero. In typical controlled machining tensile residual stresses can be induced at the surface that may accelerate crack initiation. When a large flaw occurs the crack propagation rate is initially reduced under shot peen conditions. This is As the flaw depth decreases, approaching the peak residual stresses, it is more prone to resisting propagation. Historically, most considerations for initial flaw size is in depth based on nondestructive testing s minimum threshold for crack detection [4], and although conservative, is a representative point for calculating crack propagation. Secondary surface initiation sites also correlate to the maximum compressive residual stresses as they stall once that depth is reached. This further validates that cracks that are smaller than the peak compressive residual stress are suppressed. Since most machining defects relate to pulled out and 5
6 dragged material, or surface scratches, shot peen does appear to alleviate any negative effects these features may induce. As long as the initial flaw is smaller in depth than peak compressive residual stresses no debit in total fatigue life appears. As the peak depth is approached there appears to be some debit that may occur, however further investigation will need to take place in order to better characterize what effect that debit may be. Future evaluations may include better characterization of the flaw size and shape on the fatigue life as well as determining the effect of varying peak residual stress depth as a function of stress amplitude and mean stress. References 1. Prevey, P.S.; Hornbach, D.J; Mason, P.W. Thermal Residual Stress Relaxation and distortion in surface enhanced gas turbine engine components. Proceedings of the 17 th Heat Treating Society Conference and Exposition and the 1 st International Induction Heat Treating Symposium Ruiz, Carlos; Obabueki, Abel; Gillespie, Kathy. Evaluation of the Microstructure and Mechanical Properties of Delta Processed Alloy 718. Superalloys Cammett, J.T.; Prevey, P.S.; Jayaraman, N. The Effect of Shot Peening Coverage on Residual Stress, Cold Work, and Fatigue in a Nickel-Base Superalloy. Proceedings of ICSP Paper Cherolis, Nicholas E. Fatigue in the Aerospace Industry: Striations. Journal of Failure Analysis and Prevention :
Chapter Outline: Failure
Chapter Outline: Failure How do Materials Break? Ductile vs. brittle fracture Principles of fracture mechanics Stress concentration Impact fracture testing Fatigue (cyclic stresses) Cyclic stresses, the
More informationFracture. Brittle vs. Ductile Fracture Ductile materials more plastic deformation and energy absorption (toughness) before fracture.
1- Fracture Fracture: Separation of a body into pieces due to stress, at temperatures below the melting point. Steps in fracture: 1-Crack formation 2-Crack propagation There are two modes of fracture depending
More informationCreep failure Strain-time curve Effect of temperature and applied stress Factors reducing creep rate High-temperature alloys
Fatigue and Creep of Materials Prof. A.K.M.B. Rashid Department of MME BUET, Dhaka Fatigue failure Laboratory fatigue test The S-N Ncurve Fractography of fractured surface Factors improving fatigue life
More informationTHE EFFECT OF SHOT PEENING COVERAGE ON RESIDUAL STRESS, COLD WORK AND FATIGUE IN A NICKEL-BASE SUPERALLOY
SURFACE CHARACTERISTICS THE EFFECT OF SHOT PEENING COVERAGE ON RESIDUAL STRESS, COLD WORK AND FATIGUE IN A NICKEL-BASE SUPERALLOY J.T. Cammett US. Naval Aviation Depot, Cherry Pomt, NC, USA P.S. Prevey
More informationAssessment of shot-peening on fatigue life of Inconel 718 turbine disk
Assessment of shot-peening on fatigue life of Inconel 718 turbine disk Jean-Patrick Goulmy a,b, V. Boyer a,c, L. Toualbi b, P. Kanoute b, S. Kruch b, D. Retraint c, E. Rouhaud c, A. Seror d, Q. Puydt a
More informationDWELL NOTCH LOW-CYCLE FATIGUE PERFORMANCE OF POWDER METAL ALLOY 10
DWELL NOTCH LOW-CYCLE FATIGUE PERFORMANCE OF POWDER METAL ALLOY 10 Dan Greving, Pete Kantzos, Jim Neumann, Derek Rice and Harry Kington Honeywell Engines, 111 South 34th St., Phoenix, AZ 85034, USA Keywords:
More informationIntroduction to Materials Science, Chapter 8, Failure. Failure. Ship-cyclic loading from waves.
Failure Ship-cyclic loading from waves. Computer chip-cyclic thermal loading. University of Tennessee, Dept. of Materials Science and Engineering 1 Chapter Outline: Failure How do Materials Break? Ductile
More informationChapter Outline: Failure
Chapter Outline: Failure How do Materials Break? Ductile vs. brittle fracture Principles of fracture mechanics Stress concentration Impact fracture testing Fatigue (cyclic stresses) Cyclic stresses, the
More informationTHE INFLUENCE OF SURFACE ENHANCEMENT BY LOW PLASTICITY BURNISHING ON THE CORROSION FATIGUE PERFORMANCE OF 7475-T7351 AND 2024-T351
THE INFLUENCE OF SURFACE ENHANCEMENT BY LOW PLASTICITY BURNISHING ON THE CORROSION FATIGUE PERFORMANCE OF 7475-T7351 AND 224-T351 D. Hornbach 1, P. Prevéy 1, M. Piche 2, D. Rivest 2 1 Lambda Research,
More informationFractography: The Way Things Fracture
Fractography: The Way Things Fracture S.K. Bhaumik Materials Science Division Council of Scientific & Industrial Research (CSIR) Bangalore 560 017 Outline Introduction Classification of fracture Fracture
More informationIntroduction to Engineering Materials ENGR2000 Chapter 8: Failure. Dr. Coates
Introduction to Engineering Materials ENGR2000 Chapter 8: Failure Dr. Coates Canopy fracture related to corrosion of the Al alloy used as a skin material. 8.2 Fundamentals of Fracture Fracture is the separation
More informationUse of Residual Compression in Design to Improve Damage Tolerance in Ti-6Al-4V Aero Engine Blade Dovetails
Lambda Technologies Ph: (513) 561-883 Toll Free/US: (8) 883-851 Tolerance in Ti-6Al-4V Aero Engine Blade Dovetails Paul S. Prevéy, (pprevey@lambda-research.com) N. Jayaraman, (njayaraman@lambda-research.com)
More informationElectronics materials - Stress and its effect on materials
Electronics materials - Stress and its effect on materials Introduction You will have already seen in Mechanical properties of metals that stress on materials results in strain first elastic strain and
More informationImproving Corrosion Fatigue Performance of AA2219 Friction Stir Welds with Low Plasticity Burnishing
Improving Corrosion Fatigue Performance of AA2219 Friction Stir s with Low Plasticity Burnishing P. Prevéy D. Hornbach P. Mason Lambda Research M. Mahoney Rockwell Scientific Abstract Low Plasticity Burnishing
More informationSURFACE EFFECTS ON LOW CYCLE FATIGUE BEHAVIOR IN IN718 ALLOY
SURFACE EFFECTS ON LOW CYCLE FATIGUE BEHAVIOR IN IN78 ALLOY Prabir R. Bhowal, Darryl Stolz, Agnieszka M. Wusatowska-Sarnek, Rick Montero Pratt & Whitney; 0 Main Str.; M/S 4-; East Hartford, CT 068, USA
More informationMetallurgical Defect: Manufacturing of a Reference Specimen for NDE Studies
13th International Symposium on Nondestructive Characterization of Materials (NDCM-XIII), 20-24 May 2013, Le Mans, France www.ndt.net/?id=15501 More Info at Open Access Database www.ndt.net/?id=15501 Metallurgical
More information1) Fracture, ductile and brittle fracture 2) Fracture mechanics
Module-08 Failure 1) Fracture, ductile and brittle fracture 2) Fracture mechanics Contents 3) Impact fracture, ductile-to-brittle transition 4) Fatigue, crack initiation and propagation, crack propagation
More informationEFFECT OF THE LCF LOADING CYCLE CHARACTERISTICS ON THE FATIGUE LIFE OF INCONEL 718 AT HIGH TEMPERATURE
EFFECT OF THE LCF LOADING CYCLE CHARACTERISTICS ON THE FATIGUE LIFE OF INCONEL 718 AT HIGH TEMPERATURE F.Taina 1,2, M. Pasqualon 2, V. Velay 1, D.Delagnes 1, P. Lours 1. 1-Université de Toulouse Institut
More informationELEVATED-TEMPERATURE CREEP-FATIGUE CRACK-GROWTH BEHAVIOR OF NICKEL- BASED HAYNES R-41, HAYNES 230 and HASTELLOY X AllOYS
ELEVATED-TEMPERATURE CREEP-FATIGUE CRACK-GROWTH BEHAVIOR OF NICKEL- BASED HAYNES R-41, HAYNES 230 and HASTELLOY X AllOYS S.Y. Lee 1, P.K. Liaw 1, Y.L. Lu 1, D. Fielden 1, L.M. Pike 2 and D.L. Klarstrom
More informationEFFECT OF SHOT PEENING ON FATIGUE PERFORMANCE OF TWO TITANIUM ALLOYS. H. Bae, B. Flinn, M. Ramulu, G. Weber* and H. Diep*
EFFECT OF SHOT PEENING ON FATIGUE PERFORMANCE OF TWO TITANIUM ALLOYS ABSTRACT H. Bae, B. Flinn, M. Ramulu, G. Weber* and H. Diep* University of Washington, Seattle WA, USA * The Boeing Company, Seattle
More informationEffects of Laser Peening, and Shot Peening on Friction Stir Welding
Effects of Laser Peening, and Shot Peening on Friction Stir Welding Omar Hatamleh, PhD omar.hatamleh1@.hatamleh1@jsc.nasa.gov Structural Engineering Division NASA Johnson Space Center Lloyd Hackel, Jon
More informationInfluence of Shot Peening on the Fatigue Resistance of Sulfuric Anodized AA 7175-T74
Influence of Shot Peening on the Fatigue Resistance of Sulfuric Anodized AA 7175-T74 H.J. C. Voorwald 1 a, T. A. Minto 1,b, M. Y. Pitanga 2,c, M. C. Fonseca 3,d 1 UNESP Department of Materials and Technology,
More informationCREEP AND FATIGUE CRACK GROWTH IN SEVERAL CAST SUPERALLOYS
CREEP AND FATIGUE CRACK GROWTH IN SEVERAL CAST SUPERALLOYS P. Shahinian and K. Sadananda Material Science & Technology Division Naval Research Laboratory Washington, DC 20375 Summary Crack growth behavior
More informationUse of Residual Compression in Design to Improve Damage Tolerance in Ti-6Al-4V Aero Engine Blade Dovetails
Tolerance in Ti-6Al-4V Aero Engine Blade Dovetails Paul S. Prevéy, (pprevey@lambda-research.com) N. Jayaraman, (njayaraman@lambda-research.com) Lambda Research, 5521 Fair Lane, Cincinnati, OH 45227 Ravi
More informationDevelopment of Machining Procedures to Minimize Distortion During Manufacture
Development of Machining Procedures to Minimize Distortion During Manufacture D. Hornbach and P. Prevéy Lambda Research ABSTRACT Distortion during machining can result in high scrap rates and increased
More informationRestoring Fatigue Performance Of Corrosion Damaged Aa7075-T6 and Fretting in 4340 Steel with Low Plasticity Burnishing
Restoring Fatigue Performance Of Corrosion Damaged Aa775-T6 and Fretting in 434 Steel with Low Plasticity Burnishing Paul S. Prevéy Lambda Research John T. Cammett NAVAIR ABSTRACT Corrosion related fatigue
More informationFatigue Properties of Nitrided Alloy 718 at Elevated Temperature
Copyright 2010 Tech Science Press SL, vol.3, no.3, pp.191-199, 2010 Fatigue Properties of Nitrided Alloy 718 at Elevated Temperature N. Kawagoishi 1, A. Ohkubo 2, S. Yoshimi 3, K. Yamane 4 and K. Morino
More informationTHE EFFECT OF ELECTROCHEMICAL MACHINING ON THE FATIGUE STRENGTH OF HEAT RESISTANCE ALLOYS
Fatigue of Aircraft Structures Vol. 1 (2011) 57-63 10.2478/v10164-010-0038-2 THE EFFECT OF ELECTROCHEMICAL MACHINING ON THE FATIGUE STRENGTH OF HEAT RESISTANCE ALLOYS Jerzy Kozak Institute of Aviation,Warsaw,
More informationCOVERAGE EFFECTS IN SHOT PEENING OF AL 2024-T4
296 ICSP9 : SHOT PEENING COVERAGE EFFECTS IN SHOT PEENING OF AL 2024-T4 T. Ludian and L. Wagner Institute of Materials Science and Engineering, Clausthal University of Technology, Germany INTRODUCTION
More informationENGR 151: Materials of Engineering LECTURE #12-13: DISLOCATIONS AND STRENGTHENING MECHANISMS
ENGR 151: Materials of Engineering LECTURE #12-13: DISLOCATIONS AND STRENGTHENING MECHANISMS RECOVERY, RECRYSTALLIZATION, AND GRAIN GROWTH Plastically deforming metal at low temperatures affects physical
More informationINGE Engineering Materials. Chapter 7: Part 2. Mechanical Failure. INGE Engineering Materials. Failure Analysis
Chapter 7: Part 2 Mechanical Failure This is just an introduction to failure analysis, a much more complex area of materials engineering. Failure Analysis Fractography: The study of fracture Analysis of
More informationEFFECT OF LASER PEENING ON FATIGUE PRPOERTIES FOR AIRCRAFT STRUCTURE PARTS
EFFECT OF LASER PEENING ON FATIGUE PRPOERTIES FOR AIRCRAFT STRUCTURE PARTS T. Adachi 1, H. Takehisa 1, M. Nakajima 1, Y. Sano 2 1 Fuji Heavy Industries Ltd., 1-1-11 Yonan, Utsunomiya, 320-8564, Japan 2
More informationSHOT PEENING OF NITRIDED LAYER
SHOT PEENING OF NITRIDED LAYER A. Nakonieczny, G. Monka, I. Pokorska Institute of Precision Mechanics, Duchnicka 3, 01-796 Warsaw, Poland ABSTRACT Shot-peening is a method widely used in industrial practice
More informationEVALUATION OF THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF DELTA PROCESSED ALLOY 718. Carlos Ruiz, Abel Obabueki*, and Kathy Gillespie
EVALUATION OF THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF DELTA PROCESSED ALLOY 718 Carlos Ruiz, Abel Obabueki*, and Kathy Gillespie Allied-Signal Aerospace Company Garrett Engine Division 111 S. 34th
More informationThe Effect of Surface Enhancement on the Corrosion Properties, Fatigue Strength, and Degradation of Aircraft Aluminum
Paper No. 187 21 The Effect of Surface Enhancement on the Corrosion Properties, Fatigue Strength, and Degradation of Aircraft Aluminum Jeremy E. Scheel Paul S. Prevéy III and Douglas J. Hornbach Lambda
More informationImproved HCF Performance and FOD Tolerance of Surface Treated Ti Compressor Blades
Improved HCF Performance and FOD Tolerance of Surface Treated Ti-6-2-4-6 Compressor Blades Paul S. Prevéy Director of Research,, Cincinnati, OH 45227-341 N. Jayaraman Director of Materials Research,, Cincinnati,
More informationMSE200 Lecture 9 (CH ) Mechanical Properties II Instructor: Yuntian Zhu
MSE200 Lecture 9 (CH. 7.1-7.2) Mechanical Properties II Instructor: Yuntian Zhu Objectives/outcomes: You will learn the following: Fracture of metals. Ductile and brittle fracture. Toughness and impact
More informationCH 6: Fatigue Failure Resulting from Variable Loading
CH 6: Fatigue Failure Resulting from Variable Loading Some machine elements are subjected to statics loads and for such elements, statics failure theories are used to predict failure (yielding or fracture).
More informationAvailable online at ScienceDirect. XVII International Colloquium on Mechanical Fatigue of Metals (ICMFM17)
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 74 ( 2014 ) 273 278 XVII International Colloquium on Mechanical Fatigue of Metals (ICMFM17) Shot peening intensity optimization
More informationCarbides and Their Influence on Notched Low Cycle Fatigue Behavior of Fine- Grained IN718 Gas Turbine Disk Material
Superalloys 718, 625, 706 and Derivatives 2005 Edited by E.A. Loria TMS (The Minerals, Metals & Materials Society), 2005 Carbides and Their Influence on Notched Low Cycle Fatigue Behavior of Fine- Grained
More informationTypes of Fatigue. Crack Initiation and Propagation. Variability in Fatigue Data. Outline
Types of Fatigue Outline Fatigue - Review Fatigue crack initiation and propagation Fatigue fracture mechanics Fatigue fractography Crack propagation rate Example Factors affecting fatigue - Design factors
More informationNotch fatigue resistance of shot peened high-strength aluminium alloys: The role of residual stress relaxation
UNIVERSITÀ DI PISA Notch fatigue resistance of shot peened high-strength aluminium alloys: 1, V. Fontanari 1, C. Santus 2 1 Department of Materials Engineering and Industrial Technologies, University of
More informationControlled Plasticity Burnishing to Improve the Performance of Friction Stir Processed Ni-Al Bronze
Controlled Plasticity Burnishing to Improve the Performance of Friction Stir Processed Ni-Al Bronze Paul S. Prevey 1,a, Douglas J. Hornbach 2,b, Dr. N. Jayaraman 3,c 1,2,3 Lambda Technologies, 5521 Fair
More informationFAILURE ANALYSIS OF MINE SHAFT HOIST BRAKE SPRINGS
Steel Image Inc., Failure Analysis and Metallography 7 Innovation Drive, Suite 155, Flamborough Ontario, Canada, L9H 7H9, (289) 895-8363 FAILURE ANALYSIS OF MINE SHAFT HOIST BRAKE SPRINGS EXAMPLE REPORT
More informationOVERVIEW OF LOW PLASTICITY BURNISHING FOR MITIGATION OF FATIGUE DAMAGE MECHANISMS
Lambda Technologies Ph: (513) 561-883 Toll Free/US: (8) 883-851 OVERVIEW OF LOW PLASTICITY BURNISHING FOR MITIGATION OF FATIGUE DAMAGE MECHANISMS Paul S. Prevéy and N. Jayaraman Lambda Research, 5521,
More informationMechanical Properties
Mechanical Properties Elastic deformation Plastic deformation Fracture Fatigue Environmental crack growth Crack Instabilty ß σ T The critical crack length for given σ a a c = Q 2 K Ic σ a 2 a r ß a Sources
More informationenvironment were compared and discussed.
28 TH INTERNATIONAL CONGRESS OF THE AERONAUTICAL SCIENCES ENGINEERING FAILURE MODES AND FRACTURE CHARACTERISTICS OF SINGLE CRYSTAL SUPERALLOY BLADES He Yuhuai, Liu Changkui Beijing Institute of Aeronautical
More informationSYSTEMATIC EVALUATION OF MICROSTRUCTURAL EFFECTS ON THE MECHANICAL PROPERTIES OF ATI 718PLUS ALLOY
SYSTEMATIC EVALUATION OF MICROSTRUCTURAL EFFECTS ON THE MECHANICAL PROPERTIES OF ATI 718PLUS ALLOY R.M. Kearsey 1, J. Tsang 1, P. Au 1, S. Oppenheimer 2 and E. McDevitt 2 1 Structures and Materials Performance
More informationStudies on EC Inspection and Modeling toward MAPOD Applications
Studies on EC Inspection and Modeling toward MAPOD Applications B. F. Larson and N. Nakagawa This material is in part based on work supported by the Air Force Research Laboratory under contract #FA8650-040C-5228
More informationDWELL NOTCH LOW CYCLE FATIGUE BEHAVIOR OF A POWDER METALLURGY NICKEL DISK ALLOY
DWELL NOTCH LOW CYCLE FATIGUE BEHAVIOR OF A POWDER METALLURGY NICKEL DISK ALLOY J. Telesman 1, T.P. Gabb 1, Y. Yamada 2, L.J. Ghosn 1, D. Hornbach 3, N. Jayaraman 3 1 NASA Glenn Research Center, Cleveland,
More informationFailure and Fracture. Failure and Fracture. Outline. Design Strength and Safety Factors. where N is the.
Failure and Fracture Outline failure of engineering materials is an undesirable occurrence!! can lead to loss of human life economic losses prevention is through good design and materials selection Failure
More informationEffect of grain size for the tensile strength and the low cycle fatigue at elevated temperature of alloy 718 cogged by open die forging press
Superalloys 718, 625, 706 and Derivatives 2005 Edited by E.A. Loria TMS (The Minerals, Metals & Materials Society), 2005 Effect of grain size for the tensile strength and the low cycle fatigue at elevated
More informationFollow this and additional works at: Part of the Mechanical Engineering Commons
Worcester Polytechnic Institute Digital WPI Mechanical Engineering Faculty Publications Department of Mechanical Engineering 1-1-2012 Effects of Processing Residual Stresses on Fatigue Crack Growth Behavior
More informationAt the end of this lesson, the students should be able to understand
Instructional Objectives At the end of this lesson, the students should be able to understand Mean and variable stresses and endurance limit S-N plots for metals and non-metals and relation between endurance
More informationLIST OF FIGURES Figure 1.1: Figure 1.2: Figure 1.3: Figure 2.1: Figure 2.2: Figure 2.3: Figure 2.4: Figure 2.5: (a) (b) (c): (d) (e) (f):
LIST OF FIGURES Figure 1.1: Types of surface coatings....4 Figure 1.2: PVD processing techniques...8 Figure 1.3: Schematic of PVD process... 11 Figure 2.1: Formation of intrusion and extrusion marks on
More informationMicrostructural analysis of thermal fatigue damage in 316L pipes
Microstructural analysis of thermal fatigue damage in 316L pipes Sergio González Ana Ruiz Karl-Fredrik Nilsson 2013 Report EUR 26445 EN European Commission Joint Research Centre Institute for Energy and
More informationhttp://www.diva-portal.org This is the published version of a paper presented at International Conference on Residual Stresses, 3-7 July 2016, Sydney, Australia. Citation for the original published paper:
More informationSMM 3622 Materials Technology 3.1 Fatigue
SMM 3622 Materials Technology 3.1 Fatigue ISSUES TO ADDRESS... MECHANICAL FAILURE FATIGUE What is fatigue? Types of fatigue loading? Empirical data Estimating endurance/fatigue strength Strategies for
More informationULTRASONIC FATIGUE STRENGTH IN INCONEL 718
ULTRASONIC FATIGUE STRENGTH IN INCONEL 718 Q. hen', N. Kawagoishil, K. Othubol, E. Kondol M. ~akai', and T. Kizaki2 1 Kagoshima University, Department of Mechanical Engineering 1-21-40 Korimoto Kagoshima
More informationStructures should be designed in such a way that they do not fail during their expected / predicted safe-life
Structures Any structure is built for a particular purpose Aircraft, Ship, Bus, Train Oil Platforms Bridgesand Buildings Towers for Wind energy, Electricaltransmission etc. Structures and Materials Structuresare
More informationStudy of Failure Analysis of Gas Turbine Blade
IOSR Journal of Engineering (IOSRJEN) ISSN: 2250-3021 ISBN: 2878-8719 PP 37-43 National Symposium on engineering and Research Study of Failure Analysis of Gas Turbine Blade Patil A.A.*, Shirsat U.M. Department
More informationChapter 9 Shake, rattle and roll: cyclic loading, damage and failure
Lecture notes version 26 Oct 2011 Chapter 9 Shake, rattle and roll: cyclic loading, damage and failure 9.1 Introduction and synopsis Fatigue failure is insidious (sluipend) damage accumulates over a long
More informationFatigue failure & Fatigue mechanisms. Engineering Materials Chedtha Puncreobutr.
Fatigue failure & Fatigue mechanisms Engineering Materials 2189101 Department of Metallurgical Engineering Chulalongkorn University http://pioneer.netserv.chula.ac.th/~pchedtha/ Fracture Mechanism Ductile
More informationFatigue Crack Growth Mechanisms in a Forged IN 718 Nickel-Based Superalloy. C. Mercer and W. 0. Soboyejo
Fatigue Crack Growth Mechanisms in a Forged IN 718 Nickel-Based Superalloy C. Mercer and W. 0. Soboyejo Department of Materials Science and Engineering, The Ohio State University, 2041 College Road, Columbus,
More informationCOMPARISON OF REALISTIC ARTIFICIAL CRACKS AND IN- SERVICE CRACKS
COMPARISON OF REALISTIC ARTIFICIAL CRACKS AND IN- SERVICE CRACKS Mika Kemppainen, Iikka Virkkunen (Trueflaw Ltd., P.O.Box 540, FIN-02151 Espoo, Finland) (mika.kemppainen@trueflaw.com, iikka.virkkunen@trueflaw.com)
More informationEFFECT OF WIRE-EDM CUTTING ON FATIGUE STRENGTH OF AZ61 MAGNESIUM ALLOY. Mohd Ahadlin Mohd Daud *, Mohd Zaidi Omar, Junaidi Syarif Zainuddin Sajuri
Jurnal Mekanikal June 2010, No. 30, 68-76 EFFECT OF WIRE-EDM CUTTING ON FATIGUE STRENGTH OF AZ61 MAGNESIUM ALLOY Mohd Ahadlin Mohd Daud *, Mohd Zaidi Omar, Junaidi Syarif Zainuddin Sajuri Department of
More informationLOW COST CORROSION DAMAGE MITIGATION AND IMPROVED FATIGUE PERFORMANCE OF LOW PLASTICITY BURNISHED 7075-T6
LOW COST CORROSION DAMAGE MITIGATION AND IMPROVED FATIGUE PERFORMANCE OF LOW PLASTICITY BURNISHED 7075-T6 Paul S. Prevéy Lambda Research, Cincinnati, OH John Cammett Naval Aviation Depot, MCAS Cherry Point,
More informationProperties of Cold Work Tool Steel Shot Peened by 1200 HV-Class Fe-Cr-B Gas Atomized Powder as Shot Peening Media
Materials Transactions, Vol. 51, No. 4 (20) pp. 735 to 739 #20 The Japan Institute of Metals Properties of Cold Work Tool Steel Shot Peened by 1200 HV-Class Fe-Cr-B Gas Atomized Powder as Shot Peening
More informationEffect of Cooling and Shot Peening on Residual Stresses and Fatigue Performance of Milled Inconel 718
Effect of Cooling and Shot Peening on Residual Stresses and Fatigue Performance of Milled Inconel 718 Zhe Chen 1, a *, Ru Lin Peng 1, b, Johan Moverare 1, c, Olle Widman 2, d, David Gustafsson 3, e, Sten
More informationXRD RESIDUAL STRESS MEASUREMENTS ON ALLOY 600 PRESSURIZER HEATER SLEEVE MOCKUPS
XRD RESIDUAL STRESS MEASUREMENTS ON ALLOY 6 PRESSURIZER HEATER SLEEVE MOCKUPS J. F. Hall, J. P. Molkenthin - ABB-Combustion Engineering Nuclear Power Paul S. Prevéy Lambda Research ABSTRACT Alloy 6 penetrations
More informationThermomechanical fatigue crack growth in a cast polycrystalline superalloy
MATEC Web of Conferences 4, 94 (24) DOI:.5/matecconf/24494 c Owned by the authors, published by EDP Sciences, 24 Thermomechanical fatigue crack growth in a cast polycrystalline superalloy Johan J. Moverare,2,a,
More informationDamage Tolerance of Alloy 718 Turbine Disc Material
Damage Tolerance of Alloy 718 Turbine Disc Material M. Chang, P. Au**, T. Terada**, and AK. Koul** * Dept of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Canada ** Structures and
More informationStress cycles: Dr.Haydar Al-Ethari
Dr.Haydar Al-Ethari Lecture #17/ Fatigue in metals: Fatigue is a degradation of mechanical properties leading to failure of a material or a component under cyclic loading. (This definition excludes the
More informationQuiz 1 - Mechanical Properties and Testing Chapters 6 and 8 Callister
Quiz 1 - Mechanical Properties and Testing Chapters 6 and 8 Callister You need to be able to: Name the properties determined in a tensile test including UTS,.2% offset yield strength, Elastic Modulus,
More informationUSING XRD ELASTIC AND PLASTIC STRAIN DATA TO EVALUATE THE EFFECTIVENESS OF DIFFERENT COLD-WORKING TECHNIQUES IN AEROSPACE MATERIALS
51 USING XRD ELASTIC AND PLASTIC STRAIN DATA TO EVALUATE THE EFFECTIVENESS OF DIFFERENT COLD-WORKING TECHNIQUES IN AEROSPACE MATERIALS Beth S. Matlock, Technology for Energy Corp., Knoxville, TN, USA Daniel
More informationIII Fatigue Models. 1. Will a crack nucleate? 2. Will it grow? 3. How fast will it grow?
III Fatigue Models 1. Will a crack nucleate? 2. Will it grow? 3. How fast will it grow? Outline Sources of knowledge Modeling Crack nucleation Non propagating cracks Crack growth AM 11/03 2 Source of knowledge
More informationHIGH CYCLE FATIGUE OF AN ORTHORHOMBIC TI-22AL- 25NB INTERMETALLIC ALLOY
HIGH CYCLE FATIGUE OF AN ORTHORHOMBIC TI-22AL- 25NB INTERMETALLIC ALLOY Abstract S.Q.Li, Y.J.Cheng, J.W.Zhang and X.B.Liang Central Iron & Steel Research Institute (CISRI) No.76 Xueyuan Nanlu, Beijing
More informationDURATINET COURSE - Testing Techniques for Structures Inspection LNEC Lisbon Portugal May 2012
DURATINET - Testing Techniques for Structures Inspection METALLOGRAPHY AND FRACTOGRAPHY OF IRON AND STEEL M. J. Correia LNEC, Laboratório Nacional de Engenharia Civil, DM, Av. do Brasil, 101, 1700 066
More informationSTRAIN-LIFE ASSESSMENT OF GRAINEX MAR-M 247 FOR NASA S TURBINE SEAL TEST FACILITY
STRAIN-LIFE ASSESSMENT OF GRAINEX MAR-M 247 FOR NASA S TURBINE SEAL TEST FACILITY Irebert R. Delgado U.S. Army Research Laboratory Glenn Research Center Cleveland, Ohio 44135 Gary R. Halford and Bruce
More informationFatigue Life Enhancement of Welded Structures using Ultrasonic Needle Peening
Fatigue Life Enhancement of Welded Structures using Ultrasonic Needle Peening Vincent DESFONTAINE 1, Philippe MONTHERAT 2, Frédéric CHATEAU 1, Dr Olivier BRIERE 1 1 SONATS SAS, F-44475 Carquefou Cedex,
More informationStudy on Estimation Methods of Applied Stress using Fractography Analysis
156 Study on Estimation Methods of Applied Stress using Fractography Analysis Hideaki Kaneko* 1 Hiroshi Ishikawa* 1 Takashi Konishi* 1 Masahiro Yamada* 1 The damage mode and applied stress must be estimated
More informationThe Effect of Low Plasticity Burnishing (LPB) on the HCF Performance and FOD Resistance of Ti-6Al-4V
The Effect of Low Plasticity Burnishing (LPB) on the HCF Performance and FOD Resistance of Paul S. Prevéy, Lambda Research Michael J. Shepard and Paul R. Smith, AFRL/MLLMP ABSTRACT Low Plasticity Burnishing
More informationElectron Beam Melted (EBM) Co-Cr-Mo Alloy for Orthopaedic Implant Applications Abstract Introduction The Electron Beam Melting Process
Electron Beam Melted (EBM) Co-Cr-Mo Alloy for Orthopaedic Implant Applications R.S. Kircher, A.M. Christensen, K.W. Wurth Medical Modeling, Inc., Golden, CO 80401 Abstract The Electron Beam Melting (EBM)
More informationEFFECT OF SHOT PEENING ON FATIGUE PERFORMANCE OF ADVANCED ALUMINIUM ALLOYS AND ALUMINIUM BASED METAL MATRIX COMPOSITES
EFFECT OF SHOT PEENING ON FATIGUE PERFORMANCE OF ADVANCED ALUMINIUM ALLOYS AND ALUMINIUM BASED METAL MATRIX COMPOSITES Hill S.', Gregson P.J.' and O'Hara P." 'Engineering Materials, Univers.@ of Southampton,
More informationMechanical Properties
Mechanical Properties Elastic deformation Plastic deformation Fracture Fatigue Environmental crack growth Crack Instabilty ß σ T The critical crack length for given σ a a c = Q 2 K Ic σ a 2 a r ß a Sources
More informationReading assignment. Nondestructive evaluation (NDE) Nondestructive testing (NDT) Penetrant. Conventional NDE mthods. Topic 7
Reading assignment Nondestructive evaluation (NDE) Topic 7 Notes on Nondestructive Evaluation in the course website. Sec. 8.2, 8.3 and 8.4, William Callister, Materials Science and Engineering, 6 th Ed.
More informationNONDESTRUCTIVE QUANTIFICATION OF INDUCED SURFACE TREATMENT AND RELAXATION EFFECTS IN METALS
NONDESTRUCTIVE QUANTIFICATION OF INDUCED SURFACE TREATMENT AND RELAXATION EFFECTS IN METALS D. Akers and C. Rideout Positron Systems, Inc., Boise, Idaho, USA Abstract: Photon Induced Positron Annihilation
More informationInfluence of burnishing on stress corrosion cracking susceptibility of duplex steel
of Achievements in Materials and Manufacturing Engineering VOLUME 19 ISSUE 1 November 26 Influence of burnishing on stress corrosion cracking susceptibility of duplex steel J. Łabanowski*, A. Ossowska
More informationEFFECT OF LOCAL PLASTIC STRETCH OM TOTAL FATIGUE LIFE EVALUATION
EFFECT OF LOCAL PLASTIC STRETCH OM TOTAL FATIGUE LIFE EVALUATION Abstract G. S. Wang Aeronautics Division, The Swedish Defence Research Agency SE-17290 Stockholm, Sweden wgs@foi.se This paper shows that
More informationFatigue of metals. Subjects of interest
Fatigue of metals Chapter 12 Subjects of interest Objectives / Introduction Stress cycles The S-N curve Cyclic stress-strain curve Low cycle fatigue Structural features of fatigue Fatigue crack propagation
More informationMACHINING CONDITIONS IMPACT ON THE FATIGUE LIFE OF WASPALOY IMPACT OF GRAIN SIZE
MACHINING CONDITIONS IMPACT ON THE FATIGUE LIFE OF WASPALOY IMPACT OF GRAIN SIZE Nihad Ben Salah 1, Serafettin Engin 2 Pratt & Whitney Canada; 1000 Marie Victorin 01HC4; Longueuil; QC; J4V 2K3, Canada
More informationPART I PERFORMANCE OF MATERIALS IN SERVICE. Materials and Process Selection for Engineering Design: Mahmoud Farag
PART I PERFORMANCE OF MATERIALS IN SERVICE 1 Performance of Materials in Service I Part I discusses the different types of failure and how to prevent, or at least delay, such failures by selecting appropriate
More informationChapter 14 Fracture Mechanics
Chapter 14 Fracture Mechanics Stress Concentrations - discontinuities typically exist in structures (holes, cross-section changes, keyways, etc) - discontinuities locally increase stress (stress raisers)
More informationDamage Tolerant Design for a Cast Aluminium Alloy
Proceedings of the 9 th International Conference on Aluminium Alloys (2004) Edited by J.F. Nie, A.J. Morton and B.C. Muddle Institute of Materials Engineering Australasia Ltd 345 Damage Tolerant Design
More informationINTRODUCTION TO THE USE OF LINEAR ELASTIC FRACTURE MECHANICS IN ESTIMATING FATIGUE CRACK GROWTH RATES AND RESIDUAL STRENGTH OF COMPONENTS
INTRODUCTION TO THE USE OF LINEAR ELASTIC FRACTURE MECHANICS IN ESTIMATING FATIGUE CRACK GROWTH RATES AND RESIDUAL STRENGTH OF COMPONENTS 1. INTRODUCTION This Item introduces the concepts of linear elastic
More informationFATIGUE LOADING IN WIND TURBINES
FATIGUE LOADING IN WIND TURBINES M. Ragheb 3/8/2018 INTRODUCTION Because of the complex systems of variable loads that wind turbines are subjected to, they are particularly susceptible to fatigue damage.
More informationY.S. Pyoun 1, 2, I.H. Cho 2, C.M. Suh 3, J. Park 4, J. Rogers 5, R. Kayumov 1 and R. Murakami 6
Application of UNSM (Ultrasonic Nanocrystal Surface Modification) Technology for Prolonging the Service life of AISI 1045 Shear Pin in the Flange Yoke Assembly of Stainless Hot Rolling Mill Y.S. Pyoun
More informationAvailable online at ScienceDirect. Procedia Engineering 133 (2015 ) th Fatigue Design conference, Fatigue Design 2015
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 133 (2015 ) 465 476 6th Fatigue Design conference, Fatigue Design 2015 Fatigue Strength Improvement of Aluminum and High Strength
More informationHigh-cycle fatigue characteristics of squeezed cast aluminum alloy smooth specimens cut from car wheels
High Performance Structure and Materials VI 95 High-cycle fatigue characteristics of squeezed cast aluminum alloy smooth specimens cut from car wheels M. Goto 1, N. Teshima 2, S. Z. Han 3, K. Euh 3 & T.
More informationDamage Tolerant Design for a Cast Aluminium Alloy
MATERIALS FORUM VOLUME 28 - Published 2004 Edited by J.F. Nie, A.J. Morton and B.C. Muddle Institute of Materials Engineering Australasia Ltd 345 Damage Tolerant Design for a Cast Aluminium Alloy W.J.
More information