Changes in lattice-strain profiles around a fatigue crack through the retardation period after overloading

Sun, Yunfei; An, Ke; Tang, Fei; Hubbard, Camden R.; Lu, Yu‐Lin; Choo, Hahn; Liaw, Peter K.

doi:10.1016/j.physb.2006.06.088

Cited by 10 publications

(7 citation statements)

References 10 publications

(12 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…10bv and 10cv. Similar differences between the loaded and unloaded states attributed to crack closure effects were also observed by Sun et al [3] in steel.…”

Section: Discussionsupporting

confidence: 85%

“…Although these individual contributions cannot be distinguished experimentally, the methodology presented by [1] provides the ability to differentiate the contributions from each mechanism. The development of plastic strain gradients and hence GND densities local to the crack tip are expected to translate to high GND densities which contribute to experimental diffraction peak broadening [2,3,17,18].…”

Section: Discussionmentioning

confidence: 99%

“…Experimental evidence by Sun et al [3] has shown that significant peak broadening local to a crack tip is caused by plasticity which is retained upon unloading. This further supports our hypothesis that diffraction peak broadening is found to be dominated by contributions from the development of geometrically necessary dislocation (GND)-controlled lattice curvature compared to stress-controlled elastic distortions.…”

Section: Introductionmentioning

confidence: 99%

“…However, of particular interest to the current study are the effects of cracks on diffraction peak broadening resulting from plastic strains developed local to the crack tip, and more particularly, the development of geometrically necessary dislocations (GNDs) which have been reported to be retained upon unloading [2,3,17,18]. Diffraction experiments local to a crack carried out on steel have shown the development of large FWHM local to the crack tip [2].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Lattice strains at cracks in single crystal titanium: Elastic distortion and GND contributions

Erinosho¹,

Dunne

2016

International Journal of Solids and Structures

View full text Add to dashboard Cite

There is evidence from diffraction experiments that significant peak broadening is measured local to crack tips and this has been attributed to the development of geometrically necessary dislocations (GNDs) which are retained upon unloading. This is reasonable due to the stress singularity found locally at the crack which is expected to activate slip on favorably oriented slip systems, potentially resulting in plastic strain gradients and geometrically necessary dislocation development. Hence, a systematic study is presented here to ascertain the contributions of both elastic distortional strain and GND density to lattice deformation local to the crack at loaded and subsequently unloaded states.The results show that whilst elastic strains dominate lattice distortion in comparison to GNDs at the loaded state i.e. at the peak load applied, these strains are largely recovered upon unloading and the contribution from GND development subsequently dominates the broadening seen. Two initial crystallographic configurations were considered. In the example in which the crystal c-axis was oriented parallel to the loading direction, the pyramidal systems contributed most to slip with basal slip system contributing to a lesser extent. However, in the example where the c-axis was oriented perpendicular to the loading direction, the pyramidal and prismatic systems were the more significant contributors to slip and the basal contributing to a lesser extent. However, basal, prismatic and c+a pyramidal slip systems were found to be active in both examples and this was attributed to significant lattice rotation driven by locally high stresses which enabled otherwise badly oriented slip systems to become favourable for slip. Finally, increases in GND density were seen upon unloading for c-axis orientation parallel with loading. This was attributed to the influence of pyramidal slip on reverse plasticity leading to diffuse GND density distributions and significant resulting lattice strains compared to that from prism slip loading

show abstract

“…10bv and 10cv. Similar differences between the loaded and unloaded states attributed to crack closure effects were also observed by Sun et al [3] in steel.…”

Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Lattice strains at cracks in single crystal titanium: Elastic distortion and GND contributions

Erinosho¹,

Dunne

2016

International Journal of Solids and Structures

View full text Add to dashboard Cite

show abstract

“…[11,12] The deep penetration capability of neutrons enables the nondestructive studies of the bulk crack closure behavior as compared to the surface crack closure phenomena observed using strain gauge. [4] Furthermore, the changes in internal strains can be measured in situ under the applied load using the load frame as a function of the distance from the crack tip.…”

Section: Introductionmentioning

confidence: 99%

Neutron and X-ray Microbeam Diffraction Studies around a Fatigue-Crack Tip after Overload

Lee

Barabash

Chung

et al. 2008

Metall Mater Trans A

Self Cite

View full text Add to dashboard Cite

An in-situ neutron diffraction technique was used to investigate the lattice-strain distributions and plastic deformation around a crack tip after overload. The lattice-strain profiles around a crack tip were measured as a function of the applied load during the tensile loading cycles after overload. Dislocation densities calculated from the diffraction peak broadening were presented as a function of the distance from the crack tip. Furthermore, the crystallographic orientation variations were examined near a crack tip using polychromatic X-ray microdiffraction combined with differential aperture microscopy. Crystallographic tilts are considerably observed beneath the surface around a crack tip, and these are consistent with the high dislocation densities near the crack tip measured by neutron peak broadening.

show abstract

Fatigue‐Crack‐Growth Behavior of Two Pipeline Steels

et al. 2016

View full text Add to dashboard Cite

The fatigue-crack-growth behavior of two types of pipeline steels, Alloy B [Fe-0.05C-1.52Mn-0.12Si-0.092Nb, weight percent (wt%)] and Alloy C (Fe-0.04C-1.61Mn-0.14Si-0.096Nb, wt%), have been investigated. Compact-tension (CT) specimens have been tested at various frequencies (10, 1, and 0.1 Hz) and different R ratios (0.1 and 0.5, R ¼ P min /P max where P min is the minimum applied load, and P max is the maximum applied load) in air. It is concluded that higher R ratios lead to faster crack-growth rates (FCGRs), while frequency does not have much influence on FCGRs. Moreover, Alloy B tends to have better fatigue resistance than Alloy C under various test conditions in air.

show abstract

Changes in lattice-strain profiles around a fatigue crack through the retardation period after overloading

Cited by 10 publications

References 10 publications

Lattice strains at cracks in single crystal titanium: Elastic distortion and GND contributions

Lattice strains at cracks in single crystal titanium: Elastic distortion and GND contributions

Neutron and X-ray Microbeam Diffraction Studies around a Fatigue-Crack Tip after Overload

Fatigue‐Crack‐Growth Behavior of Two Pipeline Steels

Contact Info

Product

Resources

About