Grain and grain boundary zone contributions to strain accumulation during creep of polycrystalline copper

Wilshire, B.; Burt, H.; Battenbough, Alun

doi:10.1016/j.msea.2005.08.078

Cited by 5 publications

(6 citation statements)

References 9 publications

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“…Data for copper also show that room-temperature prestraining of the pure metal sufficient to suppress plastic deformation upon loading in creep testing within the range of dislocation creep and intergranular fracture does not affect grain boundary damage significantly; however, this lowers the strain rate of the grain interiors, and hence of the metal 113,114,116 . These results suggest that prior cold-working of the metal (i) should lower the tensile elongation at failure in creep (constant load) deformation, and (ii) should deepen and narrow the trough under fixed strain-rate deformation.…”

Section: Influence Of Prior Cold Workmentioning

confidence: 95%

“…This is of course somewhat crude, but since the creep of copper has been the object of numerous studies focused on the steady-state creep regime (e.g., Refs. 64,65,[103][104][105][106][107][108][109][110][111][112][113][114][115][116][117][118][119], and since this simple view of the ITE phenomenon illustrates well both its origin and its intrinsic dependence on several parameters, we adopt it here.…”

Section: The Ductility Trough Of Unalloyed Coppermentioning

confidence: 99%

“…Now, the creep rate of copper depends only weakly on grain size at higher stress, both in the power-law (dislocational) creep regime (where n≈5) and near the transition to the regime where n≈1 132 . On the other hand when n≈1 (generally but not always taken to be the diffusion creep regime), the creep rate depends roughly on the inverse of the grain size squared 111,113,133 . The range of dominance of this latter (diffusion creep) regime is sketched in Fig.…”

Section: Influence Of Grain Sizementioning

confidence: 99%

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Intermediate temperature embrittlement of copper alloys

Laporte¹,

Mortensen²

2009

International Materials Reviews

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Copper and its alloys generally display a severe reduction in ductility between roughly 300°C and 600°C, a phenomenon variously called "intermediate temperature embrittlement" or "ductility trough behaviour". This review of the phenomenon begins by placing it in the wider context of the high-temperature fracture of metals, showing how its occurrence can be rationalized in simple terms on the basis of what is known of intergranular creep fracture and dynamic recrystallisation. Data in the literature are reviewed to identify main causes and mechanisms for embrittlement, first for pure copper, and then for monophase and multiphase copper alloys. Coverage then turns to the "grain boundary embrittlement" phenomenon, caused by the intergranular segregation of even minute quantities of alloying additions or impurities, which appears to worsen dramatically the intermediate temperature embrittlement of copper alloys. Finally, metal-induced embrittlement, including in particular liquid metal embrittlement, is presented as a second mechanism leading to an exacerbation of the intermediate temperature embrittlement of copper and its alloys.

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Section: Influence Of Prior Cold Workmentioning

confidence: 95%

Section: The Ductility Trough Of Unalloyed Coppermentioning

confidence: 99%

Section: Influence Of Grain Sizementioning

confidence: 99%

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Intermediate temperature embrittlement of copper alloys

Laporte¹,

Mortensen²

2009

International Materials Reviews

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“…Many authors (see, e.g., [2,7,10,[26][27][28][29]) have pointed out that dislocation density, ρ increases rapidly with increasing plastic strain. The increased dislocation density introduced by prestraining at room temperature cannot be fully recovered during the subsequent heating process prior to creep and may create strong barrier to dislocation movement during creep.…”

Section: Effects On Dislocation Substructurementioning

confidence: 99%

A review of the effect of prior inelastic deformation on high temperature mechanical response of engineering alloys

O’Dowd

Davies

et al. 2010

International Journal of Pressure Vessels and Piping

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In this review article, we examine the influence of prior deformation (prestrain) on the subsequent high temperature mechanical behaviour of engineering alloys. We review the observed effects at a macroscopic level in terms of creep deformation, creep rupture times and crack growth rates from a number of sources and a range of materials. Microstructural explanations for the observed macroscopic effects are also reviewed and constitutive models which incorporate the effect of prior deformation are examined. The emphasis in the paper is on engineering steels though reference is also made to non ferrous alloys.

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“…In pure metals, dislocation movement is hindered by dislocation-dislocation interactions and interactions with grain boundaries or precipitates. Stress change creep experiments in pure metals and some alloys [1,2,3,4] have shown that upon a modest stress drop, creep rates are initially low since the dislocation substructure does not change rapidly and the dislocations must now move through a dislocation substructure formed at higher stress. Since all dislocations have an associated stress field and the dislocation substructures may have a very inhomogeneous density, the internal stress across a material may vary greatly [5].…”

Section: Introductionmentioning

confidence: 99%

Creep behaviour of Waspaloy under non-constant stress and temperature

Harrison

Whittaker

Deen

2013

Materials Research Innovations

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Current creep models are derived using data from constant stress (or load) creep tests and are capable of accurately predicting creep behaviour when applied conditions are constant or near constant. However, analyses of creep curve shapes for the nickel based superalloy Waspaloy, when applied stress and/or temperature vary greatly during testing, have shown that predictive methods based purely on strain, time or lifefraction are insufficient and cannot predict observed creep rates. This is important when considering stress concentration features where stress relaxation due to creep can significantly alter the distribution of stress and thus affect fatigue life. When both stress and temperature are changed during a creep test, dislocation movement must proceed through a dislocation network formed under different conditions, resulting in greater than expected creep rates. It is proposed that this is due to a reduction in effective internal stress due to changes in dislocation structure.

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Grain and grain boundary zone contributions to strain accumulation during creep of polycrystalline copper

Cited by 5 publications

References 9 publications

Intermediate temperature embrittlement of copper alloys

Intermediate temperature embrittlement of copper alloys

A review of the effect of prior inelastic deformation on high temperature mechanical response of engineering alloys

Creep behaviour of Waspaloy under non-constant stress and temperature

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