Microplastic bases for constitutive relations found in tensile testing

Saimoto, S.; Sang, H.; Morris, Larry R.

doi:10.1016/0001-6160(81)90101-2

Cited by 28 publications

(12 citation statements)

References 26 publications

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“…The intersection of the two fitted curves is designated by s 3 and c 3 and suggests a change in the mode of dislocation passage. Beyond s 3 and c 3 , a Hollomon n-value of 1/(2 + b) = 1/ 3.89 corresponds to 1/3.6, determined from the master curve beyond e of 0.04 as previously determined [11]. It was observed that c 3 /3 for these tests were all above 0.04.…”

Section: Simulation Of Tensile Datasupporting

confidence: 67%

“…One of us has been pursuing this type of representation and has shown that a differential form of the modified Hollomon relation [10] is found at strains beyond 4% for polycrystalline Al [11]. Recently it was realized that a quantitative relation of k and (sos/oc) À1 is possible as suggested by theoretical analysis using the initial slope for [1 0 0] single-crystal tensile tests [12].…”

Section: Introductionmentioning

confidence: 99%

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Constitutive relation based on Taylor slip analysis to replicate work-hardening evolution

Saimoto

Houtte

2011

Acta Materialia

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Section: Simulation Of Tensile Datasupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Constitutive relation based on Taylor slip analysis to replicate work-hardening evolution

Saimoto

Houtte

2011

Acta Materialia

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“…These observations strongly indicate that changes in degree of vacancy super-saturation affect the strain-rate sensitivity. Scrutinizing Figure 14, S down for free-GB is slightly larger than those from prior studies [46], SS&M(oc) at 10 −4 s −1 and SS&M(os) at 10 −3 s −1 which were determined at high strains wherein nano-voids had formed. Another observation is that the data of less pure SS&M [46] lies above the purer Al specimens below 220 K but is nearly the same at 78 K whereby vacancies at intersection sites were not created, which suggest that vacancy formation at intersection is affected by impurity content.…”

Section: Derivation Of S For and S Debris For Free-gb Aluminummentioning

confidence: 55%

“…Hence, decrease of the processing temperature results in deferred ductile failure by void coalescence. The measured S up and S down values are plotted in Figure 14 and are compared with those of the super-pure Al from current work and that of Al single crystals [7,11], and AA1100 from prior study [46]. In the temperature range 78 K to 195 K, all the available data points for very pure Al cluster together including the fit-locus derived from S = {442.2/(T − 45)} × 10 −5 K −1 [11].…”

Section: Derivation Of S For and S Debris For Free-gb Aluminummentioning

confidence: 99%

Rate-Controlling Microplastic Processes during Plastic Flow in FCC Metals: Origin of the Variation of Strain Rate Sensitivity in Aluminum from 78 to 300 K

2022

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The thermodynamic response of dislocation intersections with forest dislocations and other deformation products is recorded using the Eyring rate relation wherein the application of shear stress increases the probability of activation at a given strain rate and temperature. The inverse activation volume, 1/ν, can be directly determined by instantaneous strain-rate change and its dependence on flow stress, τ, defines the strain-rate sensitivity, S, through the Haasen plot slope. A linear slope over a large strain interval is observed even for a heterogeneous distribution of obstacles that could be of more than one type of obstacles encountered by the gliding dislocation. It was deduced that ν and τ at each activation site are coordinated by the internal stress resulting in constant activation work (k/S). The stress changes from down-rate changes become larger than that from up-rate changes due to the formation of weaker obstacles, resulting in a composite S, whereas only forest dislocations are detected by the up-change. The additivity of 1/ν was used to separate obstacle species in specially prepared AA1100 and super-pure aluminum from 78 to 300 K. The deduction that repulsive intersection is the rate-controlling process and creates vacancies at each intersection site depending on temperature was validated by observing the pinning and depinning of dislocations via pipe diffusion above 125 K. A new method to separate S for dislocation-dislocation intersections from the intersections with other obstacles and their temperature dependence is presented and validated.

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“…Most of the e,k5-data were determined from Al-11 wt% Zn where the structure of free dislo-6 , The I-data were evaluated using the yield stress 18.7 MPa given by [18]. 7, The steady state a-i pairs were determined using the compilation of data in [12].…”

mentioning

confidence: 99%

Deformation kinetics at constant structure during work hardening and steady state deformation of pure aluminium

Blum

Pöllmann

Hofmann

et al. 1996

Phys. Stat. Sol. (a)

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Dedicated to Professor Dr. PAVEL LuKAC on the occasion of his 60th birthday Stress change tests are performed with pure polycrystalline A1 during deformation at constant stress 10 MPa 5 ( I 5 40 MPa between room temperature and 523 K. The spacings 1 of thermal obstacles derived from the stress change tests decrease as the strain rate i approaches its steady state value. This corresponds to deviations from the Cottrell-Stokes law during deformation at constant i . The decrease in 1 is discussed a s a consequence of dynamic recovery. It is shown that it can be explained by small changes in the athermal stress component caused by concurrent dynamic recovery. An reinem, polykristallinem Aluminium werden wahrend Verformung unter konstanter Spannung 10 MPa 5 (T 5 40 MPa zwischen Raumtemperatur und 523 K Spannungswechselversuche durchgefiihrt. Die hierbei ermittelten Abstande 1 der thermischen Hindernisse nehmen ab, wahrend die Verformungsgeschwindigkeit ihrem stationaren Wert zustrebt . Dies stimmt mit Abweichungen vom Cottrell-Stokes-Gesetz wahrend Verformung unter konstantem i iiberein. Die Abnahme von 1 wird als Folge dynamischer Erholung diskutiert. Es wird gezeigt, daO diese durch kleine Anderungen in der athermischen Spannungskomponente erklart werden kann, die durch die dynamische Erholung hedingt sind. ') Martensstr. 5, D-91058 Erlangen, Federal Republic of Germany. ') Often called creep test.

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Microplastic bases for constitutive relations found in tensile testing

Cited by 28 publications

References 26 publications

Constitutive relation based on Taylor slip analysis to replicate work-hardening evolution

Constitutive relation based on Taylor slip analysis to replicate work-hardening evolution

Rate-Controlling Microplastic Processes during Plastic Flow in FCC Metals: Origin of the Variation of Strain Rate Sensitivity in Aluminum from 78 to 300 K

Deformation kinetics at constant structure during work hardening and steady state deformation of pure aluminium

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