Stability of ultrafine-grained structure of copper under fatigue loading

Kunz, Ludvík; Lukáš, P.; Pantělejev, Libor; Man, Ondřej

doi:10.1016/j.proeng.2011.04.036

Cited by 16 publications

(17 citation statements)

References 7 publications

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“…However, the cyclic plastic strain imposed on to the samples are lower in many of the reported stress controlled tests [40][41][42] compared to that of the strain controlled tests [44]. As such, the observation of cyclic softening only in the case of strain controlled tests and cyclic hardening/saturation in the load controlled tests reported in Reference [44] may be simply a manifestation of the same transition from cyclic hardening to cyclic softening described above. It should be noted that in some cases for aluminum alloys, the cyclic softening response is preceded by a cyclic hardening response [47,50].…”

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 94%

“…It is worth mentioning that Kunz et al [44] have reported that cyclic softening is observed only in strain controlled tests, whereas load controlled tests generally yield cyclic hardening or cyclic saturation response. However, the cyclic plastic strain imposed on to the samples are lower in many of the reported stress controlled tests [40][41][42] compared to that of the strain controlled tests [44]. As such, the observation of cyclic softening only in the case of strain controlled tests and cyclic hardening/saturation in the load controlled tests reported in Reference [44] may be simply a manifestation of the same transition from cyclic hardening to cyclic softening described above.…”

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 99%

“…Many of the reports on the cyclic deformation behavior of SPDed metals have been based on metals processed by ECAP, e.g., for high purity copper [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38], technical purity copper [33,[39][40][41][42][43][44], aluminium and aluminum alloys [45][46][47][48][49][50][51], commercial purity titanium [52], IF steel [53,54], and α-brass [55]. There are also reports, albeit fewer in quantity, based on products of different techniques, such as high purity copper processed by HPT [36], high purity copper processed by ARB [56,57], and aluminum and aluminum alloys processed by cryogenic rolling [58,59].…”

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 99%

“…A transition from cyclic hardening response to cyclic softening response with increasing applied plastic strain amplitudes or increasing cyclic stress amplitudes can be observed in many of the cases with technical purity copper [40][41][42], and that of aluminum alloys [45][46][47][49][50][51]. It is worth mentioning that Kunz et al [44] have reported that cyclic softening is observed only in strain controlled tests, whereas load controlled tests generally yield cyclic hardening or cyclic saturation response. However, the cyclic plastic strain imposed on to the samples are lower in many of the reported stress controlled tests [40][41][42] compared to that of the strain controlled tests [44].…”

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 99%

“…A lack of grain coarsening has been noted in many of the above reports, especially in those that have only noted a minor or insignificant cyclic softening response [40][41][42]47,48,52,59]. However, grain coarsening has been reported in some cases of lower purity SPDed metals, especially those that have exhibited some extent of cyclic softening [44,51,58]. Although the extent of coarsening is commonly reported to be much lower than the case of high purity SPDed metals.…”

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 99%

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The Cyclic Deformation Behavior of Severe Plastic Deformation (SPD) Metals and the Influential Factors

Kwan

Wang

2012

Metals

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Abstract:A deeper understanding of the mechanical behavior of ultra-fine (UF) and nanocrystalline (NC) grained metals is necessary with the growing interest in using UF and NC grained metals for structural applications. The cyclic deformation response and behavior of UF and NC grained metals is one aspect that has been gaining momentum as a major research topic for the past ten years. Severe Plastic Deformation (SPD) materials are often in the spotlight for cyclic deformation studies as they are usually in the form of bulk work pieces and have UF and NC grains. Some well known techniques in the category of SPD processing are High Pressure Torsion (HPT), Equal Channel Angular Pressing (ECAP), and Accumulative Roll-Bonding (ARB). In this report, the literature on the cyclic deformation response and behavior of SPDed metals will be reviewed. The cyclic response of such materials is found to range from cyclic hardening to cyclic softening depending on various factors. Specifically, for SPDed UF grained metals, their behavior has often been associated with the observation of grain coarsening during cycling. Consequently, the many factors that affect the cyclic deformation response of SPDed metals can be summarized into three major aspects: (1) the microstructure stability; (2) the limitation of the cyclic lifespan; and lastly (3) the imposed plastic strain amplitude.

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Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 94%

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 99%

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 99%

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 99%

Section: Overview Of the Cyclic Deformation Behavior Of Spded Metalsmentioning

confidence: 99%

See 3 more Smart Citations

The Cyclic Deformation Behavior of Severe Plastic Deformation (SPD) Metals and the Influential Factors

Kwan

Wang

2012

Metals

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Influence of the ECAP Processing Parameters on the Cyclic Deformation Behavior on Ultrafine‐Grained Cubic Face Centered Metals

2012

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Ultrafine-grained (UFG) materials produced via equal channel angular pressing (ECAP) show high strength under monotonic loading as well as strongly enhanced fatigue lives in the Wö hler-S-N-plot compared to their conventionally grain sized (CG) counterparts. [1][2][3] For the AlMg model system, where the Mg content was systematically varied between 0.5 and 2 wt% by May et al., [4] where the fatigue life increases by several orders of magnitudes. Improved fatigue lives were found for many other UFG materials [3,5] like aluminum alloys, [6] copper, [7,8] titanium alloys, [9] and steels. [10][11][12] Despite the positive effects of the UFG microstructure on the monotonic behavior and fatigue life, pronounced differences became evident when comparing the data available in literature. Hence the influences of the processing parameters of the ECAP process have to be investigated in more detail.When the strain amplitude is the relevant quantity of design, fatigue life enhancement by an UFG microstructure has to be discussed carefully. As already predicted by Mughrabi and Hö ppel in 2001, a crossover between the fatigue life curves of the CG and UFG condition occurs. [13] This crossover is related to the fact that the fatigue life is dominated by the strength of the material at small plastic strain amplitudes and by the ductility of the material when the plastic strain amplitude exceeds or overcomes the elastic strain amplitude. In this context the point of crossover, also denoted as point of transition, is dependent on the materials properties and hence on the ECAP.Besides the fatigue life also the cyclic stability is strongly dependent on the processing parameters like already shown by Niendorf et al. [10][11][12] on IF steels or by Vinogradov [14] on copper.In order to understand the influence of the ECAP processing parameters on the cyclic deformation behavior and fatigue life in more detail this work focuses on the the AlMg model system with up to 2 wt% of Mg. For the comparison with commercial alloys AA6061 and AA6082 are used.

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Interface Engineering at the Nanoscale: Synthesis of Low‐Energy Boundaries

Kapp,

Eckert,

Renk

2024

Adv Eng Mater

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The low toughness and structural stability of nanostructured materials are strongly related to the numerous grain boundaries and interfaces. Among other design stratgies, the use of low‐energy boundaries has turned out to provide the most comprehensive improvement of the property spectrum targeting on ductility, toughness, as well as thermal and microstructural stability upon mechanical loading. Cyclic high‐pressure torsion (CHPT) is one prosperous technique to synthesize low‐angle boundaries (LAGB) at the nanoscale, enabling the production of high‐strength materials. It is presented here with an in‐depth analysis of the structural evolution focusing on the effect of different strain amplitudes and accumulated strains as well as crystal structure to understand how these parameters need to be adjusted to optimize the fraction of LAGBs. Different than expected from classical fatigue testing, the crystal structure seems to play a minor role for the cell structure evolution at comparably large strain amplitudes. It is, therefore, a strong asset that CHPT is feasible to produce nanostructures LAGB boundaries in both FCC and BCC structures. Furthermore, by optimizing the geometry of the anvils, it enables homogenous structural sizes in the entire sample as in contrast to other techniques the strain gradient impact on LAGB formation can be overcome.

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Stability of ultrafine-grained structure of copper under fatigue loading

Cited by 16 publications

References 7 publications

The Cyclic Deformation Behavior of Severe Plastic Deformation (SPD) Metals and the Influential Factors

The Cyclic Deformation Behavior of Severe Plastic Deformation (SPD) Metals and the Influential Factors

Influence of the ECAP Processing Parameters on the Cyclic Deformation Behavior on Ultrafine‐Grained Cubic Face Centered Metals

Interface Engineering at the Nanoscale: Synthesis of Low‐Energy Boundaries

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