Fracture behaviour of ultrafine-grained materials under static and cyclic loading

Hübner, P.; Kiessling, Rene; Biermann, Horst; Vinogradov, Alexei

doi:10.3139/146.101422

Cited by 22 publications

(10 citation statements)

References 14 publications

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“…The standard crack growth rate da/dN versus stress intensity factor range ΔK plots for the nanostructured materials showed the same stages of crack propagation as in the coarse-grained materials. However, the fatigue 'threshold' ΔK th corresponding to the low-end limit of the curves decreased after SPD processing in CP Al and a range of Al alloys [108][109][110]. Similar results were reported for CP Ti [112], where ECAP processing reduced ΔK th and led to the higher cyclic crack growth rate.…”

Section: Low-cycle Fatigue Behavior Of Nanostructured Metallic Materialssupporting

confidence: 85%

“…The LCF life is mainly controlled by fatigue crack propagation. The fatigue crack growth behavior in the NS metals was found to be different from that in the coarse-grained counterparts [108][109][110]. The standard crack growth rate da/dN versus stress intensity factor range ΔK plots for the nanostructured materials showed the same stages of crack propagation as in the coarse-grained materials.…”

Section: Low-cycle Fatigue Behavior Of Nanostructured Metallic Materialsmentioning

confidence: 77%

“…The standard crack growth rate da/dN versus stress intensity factor range ΔK plots for the nanostructured materials showed the same stages of crack propagation as in the coarse-grained materials. However, the fatigue 'threshold' ΔK th corresponding to [81] with the permission from the publisher the low-end limit of the curves decreased after SPD processing in pure Al [109], AA5056 [110], and Al-1.5MgScZr [108].…”

Section: Low-cycle Fatigue Behavior Of Nanostructured Metallic Materialsmentioning

confidence: 92%

See 2 more Smart Citations

Multifunctional Properties of Bulk Nanostructured Metallic Materials

Sabirov

Enikeev

Murashkin

et al. 2015

Bulk Nanostructured Materials With Multifunctional Properties

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This chapter focuses on multifunctional properties of bulk nanostructured metallic materials and structure-properties relationship therein. The most important structural factors affecting mechanical, physical, and chemical properties of the nanomaterials are discussed, and the strategies to their further improvement are outlined. Special attention is paid to nanostructural design for simultaneous improvement of mutually exclusive properties. Superstrength and Enhanced Mechanical PropertiesAlthough the mechanical and functional properties of all polycrystalline metallic materials are determined by several factors, the grain size of the material generally plays the most significant and often a dominant role. Thus, the strength of different polycrystalline materials is related to the grain size, d, through the Hall-Petch equation which states that the yield stress, σ y , is given bywhere σ o is termed the friction stress and k y the Hall-Petch constant [1,2]. It follows from Eq. 3.1 that the strength increases with a reduction in the grain size and this has led to an ever-increasing interest in fabricating materials with extremely small grain sizes. The fabrication of bulk samples and billets using equal channel angular pressing (ECAP), high pressure torsion (HPT), and other severe plastic deformation (SPD) techniques was a crucial first step in initiating investigations into the properties of bulk nanomaterials because the use of SPD processing permitted, and subsequently fully supported, a series of systematic studies using various nanostructured metallic materials including commercial alloys [3][4][5][6][7][8]

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Section: Low-cycle Fatigue Behavior Of Nanostructured Metallic Materialssupporting

confidence: 85%

Section: Low-cycle Fatigue Behavior Of Nanostructured Metallic Materialsmentioning

confidence: 77%

“…The standard crack growth rate da/dN versus stress intensity factor range ΔK plots for the nanostructured materials showed the same stages of crack propagation as in the coarse-grained materials. However, the fatigue 'threshold' ΔK th corresponding to [81] with the permission from the publisher the low-end limit of the curves decreased after SPD processing in pure Al [109], AA5056 [110], and Al-1.5MgScZr [108].…”

Section: Low-cycle Fatigue Behavior Of Nanostructured Metallic Materialsmentioning

confidence: 92%

See 1 more Smart Citation

Multifunctional Properties of Bulk Nanostructured Metallic Materials

Sabirov

Enikeev

Murashkin

et al. 2015

Bulk Nanostructured Materials With Multifunctional Properties

View full text Add to dashboard Cite

show abstract

“…[10][11][12][13][14][15] In this article, some results on fracture mechanics investigations of specimens of UFG Al and two Al alloys produced by the ECAP, ARB, and MAXstrain process, respectively, are presented in addition to a recent article by the authors on other materials such as copper and Ti. [16] II. EXPERIMENTAL…”

Section: Introductionmentioning

confidence: 98%

Static and Cyclic Crack Growth Behavior of Ultrafine-Grained Al Produced by Different Severe Plastic Deformation Methods

Hübner

Kiessling

Biermann

et al. 2007

Metall Mater Trans A

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Fracture-mechanics experiments were carried out on ultrafine-grained (UFG) samples of aluminum and two Al alloys to obtain the fracture behavior under static and cyclic loading. The UFG materials investigated show crack resistance behavior under static loading, which was confirmed by ductile fracture surfaces. Under cyclic load, the crack growth rate was described well by the ESACRACK model. The crack propagation results show no influence of the type of the severe plastic deformation method in the Paris region but more effect in the threshold region.

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“…10,15,16) However, the LCF properties smooth UFG samples can be considerably improved by post-ECAP annealing at moderate temperatures, which reduces the initial dislocation density, the internal stresses and the number of stress risers and also leads to relaxation of non-equilibrium, high-energy grain boundaries produced by ECAP. In particular, it was suggested that by producing bi-modal grain structures 29) with co-existing populations of small and large grains a favourable combination of strength and ductility may be achieved, which also promotes improved LCF performance.…”

Section: Effect Of Bimodal Structure On the Crack Growthmentioning

confidence: 99%

Fatigue Crack Growth and Related Microstructure Evolution in Ultrafine Grain Copper Processed by ECAP

et al. 2012

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Fatigue crack growth tests were carried out using centre-cracked tensile (CCT) specimens of ultrafine grained (UFG) copper, aiming at clarifying microstructure evolution around the fatigue crack tip and at better understanding of fatigue crack propagation mechanisms. The fatigue crack growth tests revealed that UFG copper had the lowest threshold stress intensity factor range "K th . On the other hand, the crack growth rates were almost identical among the UFG and conventional specimens tested at higher "K I regime. From the microstructure observation after the fatigue crack growth test, significant grain growth was detected in the intimate vicinity to the fracture surface in UFG copper. The size of the grown grains in the UFG copper increased with increasing stress intensity factor range and with the size of the cyclic plastic zone.

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Fracture behaviour of ultrafine-grained materials under static and cyclic loading

Cited by 22 publications

References 14 publications

Multifunctional Properties of Bulk Nanostructured Metallic Materials

Multifunctional Properties of Bulk Nanostructured Metallic Materials

Static and Cyclic Crack Growth Behavior of Ultrafine-Grained Al Produced by Different Severe Plastic Deformation Methods

Fatigue Crack Growth and Related Microstructure Evolution in Ultrafine Grain Copper Processed by ECAP

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