A compilation and analysis of data for the stress dependence of the subgrain size

Raj, S. V.; Pharr, George M.

doi:10.1016/0025-5416(86)90265-x

Cited by 284 publications

(118 citation statements)

References 9 publications

Supporting

Mentioning

115

Contrasting

Order By: Relevance

“…The change in the dislocation structure and free dislocation density can be found in the past. [44][45][46][47][48][49][50][51] The attenuation coefficient was given by substituting L 1 and L 1 for L and L in Eqs. [2] and [3].…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Creep-Induced Microstructural Evolution and Acoustic Characterization in Tempered Martensitic Stainless Steel

Ohtani

2007

Metall Mater Trans A

View full text Add to dashboard Cite

The microstructural evolution of a tempered martensitic stainless steel (a 12 pct chromium steel, type-403), during creep test, subjected to a tensile creep test at 873 K, was studied by monitoring the shear-wave attenuation and velocity using electromagnetic acoustic resonance (EMAR). The study disclosed an attenuation peak at around 20 to 30 pct of the creep life, and a minimum value at 50 pct of the creep life, and a local minimum velocity at the attenuation peak, independent of the applied stress. These novel phenomena are interpreted as a result of microstructural changes, especially dislocation recovery. This interpretation is supported by transmission electron microscopy observations of the dislocation structure. The relationship between the changes in attenuation, velocity, and microstructure evolution can be explained with the string model. The study results have suggested that EMAR possesses the potential to assess the progress of creep damage and to predict the remaining creep life of metals.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Similar results have been reported. [44,45] This evolution of the cell or subgrain corresponds well to the change in the attenuation coefficient in Figure 5. Finally, in Figure 15, we show the strong correlation between the hardness and width of the cells or subgrain.…”

Section: Microstructurementioning

confidence: 99%

Creep-Induced Microstructural Evolution and Acoustic Characterization in Tempered Martensitic Stainless Steel

Ohtani

2007

Metall Mater Trans A

View full text Add to dashboard Cite

show abstract

“…͑4͒, (1) ␣,s (r) is the density of dislocations of type ͕␣,s͖ at the position r, and (2) ␣␣Ј,ssЈ (r,rЈ) is the density of pairs of dislocations of types ͕␣,s͖ and ͕␣Ј,sЈ͖ at the respective positions r and rЈ. Higher-order densities which obey the recursive relations…”

Section: ͑4͒mentioning

confidence: 99%

“…It is noted that owing to the ensemble averaging the many-dislocation densities are in general smooth functions of their arguments. In the following, we shall often use an abbreviated notation, writing (1) (…”

Section: ͑4͒mentioning

confidence: 99%

“…In many cases the dislocations form spatial patterns with length scales which decrease in inverse proportion with the flow stress ͑''law of similitude''͒. 1 In conjunction with the Taylor relationship according to which the flow stress of a dislocation arrangement is proportional to the square root of dislocation density, this implies that the characteristic scales of deformation-induced dislocation patterns are often proportional to, but in general much larger than, the mean dislocation spacing. This holds even for ''fractal'' dislocation patterns which are self-similar over a certain range of scales, since the upper and lower bounds of this scaling regime are again proportional to the average dislocation spacing.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Statistical dynamics of dislocation systems: The influence of dislocation-dislocation correlations

2001

View full text Add to dashboard Cite

During plastic deformation of crystalline materials, the collective dynamics of interacting dislocations gives rise to various patterning phenomena. A crucial and still open question is whether the long range dislocationdislocation interactions which do not have an intrinsic range can lead to spatial patterns which may exhibit well-defined characteristic scales. It is demonstrated for a general model of two-dimensional dislocation systems that spontaneously emerging dislocation pair correlations introduce a length scale which is proportional to the mean dislocation spacing. General properties of the pair correlation functions are derived, and explicit calculations are performed for a simple special case, viz pair correlations in single-glide dislocation dynamics. It is shown that in this case the dislocation system exhibits a patterning instability leading to the formation of walls normal to the glide plane. The results are discussed in terms of their general implications for dislocation patterning.

show abstract

The constant‐hardness creep compliance of polycrystalline ice

Caswell

Cooper

Goldsby

2015

Geophysical Research Letters

View full text Add to dashboard Cite

We have performed creep and stress‐reduction experiments on polycrystalline ice (grain sizes, d ≈ 30 and ≈ 245 µm) in the grain boundary sliding and dislocation creep regimes (stresses σ = 0.5–5 MPa, temperature T = 233 K) to determine the constant‐hardness creep compliance under these conditions. Our results are consistent with a microstructural state‐variable description of dislocation‐effected deformation whose rate is accelerated by grain boundary sliding. The fine‐grained specimens reveal no subgrain boundaries, indicating that the stress‐sensitive microstructural feature upon which the state‐variable behavior is founded may be the dislocation structure of the grain boundaries. Deviations of our constant‐hardness data from the behavior predicted by the state‐variable formulation allow estimation of the viscosity of the grain boundaries, which is ~4.8 × 106 Pa s at this temperature.

show abstract

A compilation and analysis of data for the stress dependence of the subgrain size

Cited by 284 publications

References 9 publications

Creep-Induced Microstructural Evolution and Acoustic Characterization in Tempered Martensitic Stainless Steel

Creep-Induced Microstructural Evolution and Acoustic Characterization in Tempered Martensitic Stainless Steel

Statistical dynamics of dislocation systems: The influence of dislocation-dislocation correlations

The constant‐hardness creep compliance of polycrystalline ice

Contact Info

Product

Resources

About