A 3-D view on the mechanisms of short fatigue cracks interacting with grain boundaries

Schaef, W.; Marx, Michael; Vehoff, H.; Heckl, A.; Randelzhofer, P.

doi:10.1016/j.actamat.2010.11.051

Cited by 120 publications

(56 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9 (c) where crack coalescence occurs. Similar short crack propagation along crystallographic facets associated with relatively low SF was also observed in other Ni-based superalloys [25].…”

Section: Effects Of Microstructure On Short Crack Propagationsupporting

confidence: 58%

“…7 demonstrates a temporary crack arrest of CG c1a due to the large inclination (or twist) in depth at the crack tip, which is consistent with Zhai's study. Moreover, the frequently observed zig-zag path which is associated with duplex slip band cracking when a crack propagates through a grain boundary could also provide an example of the crack geometrical compatibility as the zig-zag crack path is believed to minimize the energy required to rip open the grain boundary [25,27].…”

Section: Effects Of Microstructure On Short Crack Propagationmentioning

confidence: 99%

See 1 more Smart Citation

Effects of microstructures on fatigue crack initiation and short crack propagation at room temperature in an advanced disc superalloy

Jiang

Karpasitis

Gao

et al. 2015

Materials Science and Engineering: A

View full text Add to dashboard Cite

Fatigue crack initiation and early short crack propagation behaviour in two microstructural variants of a recently developed Low Solvus, High Refractory (LSHR) disc superalloy at room temperature has been investigated by three-point bending with replication procedure.The results shows that fine gained (FG) LSHR possesses higher fatigue life due to its better crack initiation resistance, limited crack coalescence and comparable Stage I crack propagation resistance to the coarse grained (CG) LSHR, although its resistance to Stage II crack propagation is inferior. Twin boundary (TB) cracking in the relatively large grains dominates the crack initiation process along with occasional crack initiation due to slip band cracking. Activation of the primary slip systems parallel to the TB at matrix and twin and high resolved shear stress associated with high Schmid factor (SF) are required for TB crack initiation. Cracks preferentially propagate along slip bands associated with high SF slip systems after initiation. But cracks also propagate along slip bands associated with slip systems with lower SF if the inclination angle between the slip band ahead of the crack tip and the crack segment of the crack tip is small enough to enable a steady transition (or nondeflected growth) of cracks across the grain boundary.

show abstract

“…9 (c) where crack coalescence occurs. Similar short crack propagation along crystallographic facets associated with relatively low SF was also observed in other Ni-based superalloys [25].…”

Section: Effects Of Microstructure On Short Crack Propagationsupporting

confidence: 58%

Section: Effects Of Microstructure On Short Crack Propagationmentioning

confidence: 99%

Effects of microstructures on fatigue crack initiation and short crack propagation at room temperature in an advanced disc superalloy

Jiang

Karpasitis

Gao

et al. 2015

Materials Science and Engineering: A

View full text Add to dashboard Cite

show abstract

“…Schaef et al [21] showed the 3D crack propagation near the grain boundaries in a polycrystalline-modified nickel-based superalloy. However, the current method is preferable to FIB observation because our method offers a larger field of view with a workable space of more than 100 mm.…”

Section: Discussionmentioning

confidence: 99%

An automated three-dimensional internal structure observation system based on high-speed serial sectioning of steel materials

Fujisaki¹,

Yamashita²,

Yokota³

2012

Precision Engineering

View full text Add to dashboard Cite

Abstract:For three-dimensional observation of the internal structure of hard materials, we developed an automated system based on serial sectioning with precision cutting and optical microscopy. The elliptical vibration cutting device in the system created mirrored surfaces suitable for optical microscopy during the serial sectioning of steel materials. In this study, high-speed sectioning with several micron thickness and repeated precise machining to depths of up to around 1 mm were achieved with a flat-edge cutting tool. For a 3 × 3 mm area of bearing steel, a mirrored surface could be created in about 1 minute, and 400 serial sectioning images were obtained within 7 hours without additional machining processes such as cleaning or changing of tools. The three-dimensional shapes and positions of continuously distributed inclusions found deep within the bearing steels, as well as cracks originating from these inclusions, could be detected with resolutions as high as 80 × 80 nm and in a wide field of view using this system.

show abstract

“…A series of remarkable experimental studies have been reported by Marx and co-workers [59][60][61][62][63] and by Gopalan & Margolin [64]. These studies have been made on various materials, including mild steel and a Ni base superalloy, CMSX-4, and 70-30 α brass.…”

Section: Fatigue Cracks and Grain Boundaries (A) Introductory Commentsmentioning

confidence: 97%

Crossing grain boundaries in metals by slip bands, cleavage and fatigue cracks

Pineau

2015

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

The size and the character (low and large angle, special boundaries, tilt and twist boundaries, twins) of the grain boundaries (GBs) in polycrystalline materials influence their strength and their fracture toughness. Recent studies devoted to nanocrystalline (NC) materials have shown a deviation from the Hall-Petch law. Special GBs formed by Σ3 twins in face-centred cubic metals are also known to have a strong effect on the mechanical behaviour of these metals, in particular their work-hardening rate. Grain orientation influences also crack path, the fracture toughness of body-centred cubic (BCC) metals and the fatigue crack growth rate of microstructurally short cracks. This paper deals both with slip transfer at GBs and with the interactions between propagating cracks with GBs. In the analysis of slip transfer, the emphasis is placed on twin boundaries (TBs) for which the dislocation reactions during slip transfer are analysed theoretically, experimentally and using the results of atomic molecular simulations published in the literature. It is shown that in a number of situations this transfer leads to a normal motion of the TB owing to the displacement of partial dislocations along the TB. This motion can generate a de-twinning effect observed in particular in NC metals. Crack propagation across GBs is also considered. It is shown that cleavage crack path behaviour in BCC metals is largely dependent on the twist component of the GBs. A mechanism for the propagation of these twisted cracks involving a segmentation of the crack front and the existence of intergranular parts is discussed and verified for a pressure vessel steel. A similar segmentation seems to occur for short fatigue cracks although, quite surprisingly, this crossing mechanism for fatigue cracks does not seem

show abstract

A 3-D view on the mechanisms of short fatigue cracks interacting with grain boundaries

Cited by 120 publications

References 19 publications

Effects of microstructures on fatigue crack initiation and short crack propagation at room temperature in an advanced disc superalloy

Effects of microstructures on fatigue crack initiation and short crack propagation at room temperature in an advanced disc superalloy

An automated three-dimensional internal structure observation system based on high-speed serial sectioning of steel materials

Crossing grain boundaries in metals by slip bands, cleavage and fatigue cracks

Contact Info

Product

Resources

About