Effect of shot peening on the fatigue and fracture behaviour of two titanium alloys

Sridhar, B. R.; Ramachandra, K.; Padmanabhan, K. A.

doi:10.1007/bf01152145

Cited by 28 publications

(13 citation statements)

References 5 publications

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“…These observations are consistent with the existing literature on mechanical relaxation [8,9,11]. Specifically, at sufficiently low applied stresses, relaxation is either minimal or completely absent, as shown by behavior at σ max = 325 MPa (~0.3σ y ).…”

Section: Evolution Of Residual Stress State During Fatigue Loadingsupporting

confidence: 81%

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Mechanical relaxation of localized residual stresses associated with foreign object damage

Boyce

Chen

Peters

et al. 2003

Materials Science and Engineering: A

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-Foreign-object damage associated with the ingestion of debris into aircraft turbine engines can lead to a marked degradation in the high-cycle fatigue life of turbine components. This degradation is generally considered to be associated with the premature initiation of fatigue cracks at or near the damage sites; this is suspected to be due to, at least in part, the impact-induced residual stress state, which can be strongly tensile in these locations. However, recent experimental studies have shown the unexpected propensity for impact-induced fatigue crack formation at locations of compressive residual stress in the vicinity of the impact site. To address this issue, in situ and ex situ spatially-resolved X-ray diffraction and numerical modeling are utilized to show that the initial residual stress state can be strongly relaxed during the fatigue loading process.The magnitude and rate of relaxation is strongly dependent on the applied loads. For a Ti-6Al-4V turbine blade alloy, little relaxation was observed for an applied maximum stress of 325 MPa (0.35σ y , where σ y is the yield stress), and cracks tended to form in subsurface zones of tensile residual stress away from the damage sites. In contrast, at an applied maximum stress of 500 MPa (0.54σ y ), equal to the smooth-bar 10 7 -cycle endurance strength, cracks tended to form at the damage sites in zones of high stress concentration that had initially been in strong compression, but had relaxed during the fatigue loading.

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Section: Evolution Of Residual Stress State During Fatigue Loadingsupporting

confidence: 81%

“…Ti-6Al-4V (in a condition similar to that of the present study), show the marked effect of cyclic deformation properties on relaxation [11]. In IMI-685, which undergoes very little cyclic softening, cycling at a maximum stress of 0.75σ y (where σ y is the yield stress) led to a small (~10%) reduction in the peak longitudinal stress.…”

mentioning

confidence: 75%

Mechanical relaxation of localized residual stresses associated with foreign object damage

Boyce

Chen

Peters

et al. 2003

Materials Science and Engineering: A

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“…The surface roughening accelerates the fatigue crack propagation, while strain hardening retards the propagation of cracks by increasing the resistance to plastic deformation and the compressive residual stress provides a corresponding crack closure stress that reduces the driving force for crack propagation [21][22][23]. In the present study, the reason for fatigue life improvement by SP would be attributed to retardation of microcrack growth, as the positive effect on fatigue life induced by the compressive residual stress field is greater than the reduction in fatigue life caused by SPinduced higher surface roughness [8,24,25].…”

Section: Discussionmentioning

confidence: 99%

Surface Characteristics and High Cycle Fatigue Performance of Shot Peened Magnesium Alloy ZK60

Dong

Liu

Ding

et al. 2011

Journal of Metallurgy

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The current work investigated the effect of shot peening (SP) on high cycle fatigue (HCF) behavior of the hot-extruded ZK60 magnesium alloy. SP can significantly improve the fatigue life of the ZK60 alloy. After SP at the optimum Almen intensities, the fatigue strength at 10 7 cycles in the as-extruded (referred to as ZK60) and the T5 aging-treated (referred to as ZK60-T5) alloys increased from 140 and 150 MPa to 180 and 195 MPa, respectively. SP led to a subsurface fatigue crack nucleation in both ZK60 and ZK60-T5 alloys. The mechanism by which the compressive residual stress induced by shot peening results in the improvement of fatigue performance for ZK60 and ZK60-T5 alloys was discussed.

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“…The LP process variations should therefore not play a significant role in fatigue life improvements offered by LP for highly loaded components. For components carrying lower loads and exhibiting long lifetimes ( > 10 6 cycles), a significant portion of the life is spent in crack propagation [26,27]. The fact that tensile surface residual stress was not found adjacent to the laser peened area suggests that LP should not have detrimental effects on fatigue performance.…”

Section: Rankin Hill and Hackel P20mentioning

confidence: 99%

“…While a weight-function analysis is beyond the scope of the present work, it can be stated unequivocally that residual stresses resulting from LP with higher fluence and larger layer overlap would have a larger contribution to the stress intensity factor because they have higher levels of compressive stress ( Figure 5 The effects of the LP variations on total fatigue life may depend on the level of loading. For highly loaded components that exhibit short to intermediate fatigue lifetimes (e.g., 10 3 to 10 5 cycles), life is mostly spent in crack initiation [26,27]. The LP process variations should therefore not play a significant role in fatigue life improvements offered by LP for highly loaded components.…”

Section: Rankin Hill and Hackel P20mentioning

confidence: 99%

The effects of process variations on residual stress in laser peened 7049 T73 aluminum alloy

Rankin¹,

Hill²,

Hackel³

2003

Materials Science and Engineering: A

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This paper reports measurements of the distribution of residual stress with depth from the surface in laser peened coupons made of a high-strength aluminum alloy. Residual stresses were measured using slitting (also known as the crack compliance method). Measurements were made on several coupons to: compare laser peening (LP) and shot peening residual stresses; ascertain the influence of LP parameters on residual stress; determine whether tensile residual stress existed outside the peened area; assess the variation of residual stress with in-plane position relative to the layout of the laser spots used for peening; and, determine the importance of a uniform spatial distribution of laser energy within the spot. Residual stress 0.1 mm from the surface due to LP and shot peening were comparable and the depth of the compressive stress for LP was far greater than for shot peening. Variations of most LP parameters did not significantly alter residual stress at shallow depths, but greater laser energy and larger layer overlap increased residual stress at depths between 0.2 and 0.6 mm from the surface. Residual stresses adjacent to the peened area were found to be compressive. Decreased levels of surface residual stress were found when laser spots had a non-uniform distribution of laser intensity.

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Effect of shot peening on the fatigue and fracture behaviour of two titanium alloys

Cited by 28 publications

References 5 publications

Mechanical relaxation of localized residual stresses associated with foreign object damage

Mechanical relaxation of localized residual stresses associated with foreign object damage

Surface Characteristics and High Cycle Fatigue Performance of Shot Peened Magnesium Alloy ZK60

The effects of process variations on residual stress in laser peened 7049 T73 aluminum alloy

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