The growth of grain-boundary voids under stress

Hüll, D.; Rimmer, D E

doi:10.1080/14786435908243264

Cited by 891 publications

(213 citation statements)

References 6 publications

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“…Aside from this occasional, microscopic evidence, arguments for both mechanisms were centered around the stress dependence of growth processes, Hull and Rimmer (63), noting that cavitation depends on the difference between tensile and hydrostatic stress, proposed a diffusive growth theory which predicted that growth of the volume of the cavities is a linear function of the applied stress and of time. Several modification were made to this theory, with essentially the same prediction (64,65).…”

Section: Creep Cavitation and Cavity Growthmentioning

confidence: 99%

Creep cavitation in 304 stainless steel

Chen¹,

Argon²

1981

Acta Metallurgica

183

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A micromechanical analysis of deformation and fracture in creeping alloys is presented based on a mechanistic approach using continuum mechanics. The analysis was first carried out on a coarse microscopic level in which the self-consistent theory of Hill was employed to treat the steady state creep of heterogeneous alloys with coarse microstructures allowing for grain boundary sliding. Processes operating on a finer scale than the grain size such as grain boundary diffusion and surface diffusion were subsequently included in the analysis. It was found that the high stresses required for cavity nucleation occur at intergranular particles only in transients of grain boundary sliding, and that two modes of cavity growth result corresponding to rate control by each of the abovementioned diffusional processes.Creep cavitation in 304 stainless steel in the neighborhood of 0.5 Tm was studied experimentally to test these theoretical models. Our results suggest that a broad spectrum of interfacial energy may exist and that microstructural changes such as those caused by twins can alter cavitation behavior drastically. Cavities grow in most cases by grain boundary diffusion coupled with matrix creep, somewhat restricted by surface diffusion. However, the grain boundary sliding can be a dominant mode of cavity growth at high stresses and for large cavities.

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Section: Creep Cavitation and Cavity Growthmentioning

confidence: 99%

Creep cavitation in 304 stainless steel

Chen¹,

Argon²

1981

Acta Metallurgica

183

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“…Creep cavity growth by the diffusional flux of vacancies over grain boundaries has been described by Herring [11], and Hull and Rimmer [12], who propose that the driving force for vacancies to migrate to the creep cavities is a function of the applied stress. The effect of strain rate in the bulk material on the creep cavity growth was treated in finite-element calculations by Needleman and Rice [13].…”

Section: Introductionmentioning

confidence: 99%

Finite element modelling of creep cavity filling by solute diffusion

Versteylen

Szymanski

Sluiter

et al. 2018

Philosophical Magazine

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“…The Hull-Rimmer [1] model for diffusive cavity growth on a grain boundary is illustrated in Fig. 1 rapid enough so that the void retains a quasithan predicted by the rigid-grains model.…”

Section: Hull-rimmer Model and Modifica~ons Due To Plastic Creep Flowmentioning

confidence: 99%

“…Hence, using equation (6), the growth rate of widely-spaced voids is given by where 9 is defined in the text after equation (1) and where (r. is the normal stress acting on the grain boundary at the void tip,…”

Section: Hull-rimmer Model and Modifica~ons Due To Plastic Creep Flowmentioning

confidence: 99%

Plastic Creep Flow Effects in the Diffusive Cavitation of Grain Boundaries

Needleman

Rice

1983

Perspectives in Creep Fracture

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Abstract-Weanalyze the growth of cavities along grain interfaces by the combined processes of grain boundary diffusion and plastic dislocation creep in the adjoining grains. It is shown that the coupling between the processes can be expressed in terms of a parameter L, which has the dimensions of length and which is a function of material properties, temperature and applied stress; L decreases with increasing temperature and stress and has, e.g., values in the range of 0.25 to 25 pm for various pure metals when stressed to 10m3 x shear modulus at 0.5 T,. The contribution of dislocation creep to the cavity growth rate is shown to be negligible when L is comparable to or larger than the cavity spacing, but significant interactions occur. leading to growth rates very much in excess of those predicted on the basis of boundary diffusion alone, when L is comparable to or smaller than the cavity size. The coupling occurs because extensive dislocation creep allows local accommodation of matter diffused into the grain boundary from the cavity walls. The cavity growth rate is analyzed by formulating a new variational principle that governs combined processes of grain boundary diffusion and non-linear viscous creep, and by implementing this principle through the finite-element method to obtain numerical solutions. Results for the cavity growth rate are presented for a wide range of ratios of L to cavity spacing. and of cavity radius to spacing. Also, results are presented for the total growth time of cavities from an initial size to final coalescence. [6,7].However, the works mentioned neglect the influen~ of plastic creep flow on the diffusive cavitation process. Our aim here is to model the combined effects of diffusion and creep flow on cavity growth. As will be seen, at stress levels of the order 10m3 p and higher (p = shear modulus) at 0.5 T,,, (T,,, = melting temperature) interactions between diffusive transport and creep flow are typically very important, although not at much iower stresses, of the order 10e4 p at this temperature. These combined effects lead to rates of cavity enlargement which can be appreciably greater than would be the case for either mechanism acting in isolation. Indeed, the possible importance of plastic creep flow to rupture at elevated temperature is suggested indirectly by the well-known MonkmanGrant [S] correlation, in which the product i,,t, (i, = steady state creep strain rate, t, = rupture time) is sometimes found to vary only slightly over ranges of stress and temperature which correspond to large changes in both factors.A previous attempt to model the combined effects of creep and diffusion on cavity growth was made by Beere and Speight [9]. Their model constitutes only a very rough approximation, and is based on the concept of each cavity being surrounded by a spherical she11 of effectively non-peeping material, within which a Hull-Rimmer diffusive cavitation process takes place, with these shells being embedded in a matrix of uniformly creeping material. The model has been modifie...

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The growth of grain-boundary voids under stress

Cited by 891 publications

References 6 publications

Creep cavitation in 304 stainless steel

Creep cavitation in 304 stainless steel

Finite element modelling of creep cavity filling by solute diffusion

Plastic Creep Flow Effects in the Diffusive Cavitation of Grain Boundaries

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