Inherent lattice hardening and interstitial solution hardening in tantalum

Lachenmann, R.; Schultz, H.

doi:10.1016/0036-9748(70)90211-5

Cited by 44 publications

(7 citation statements)

References 24 publications

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“…The Peierls stress decreases ostensibly linearly up to a critical temperature T c , beyond which it rapidly tends to zero. These trends are in agreement with the experimental observations of Wasserb ach (1986) and Lachenmann and Schultz (1970). The critical temperature T c increases with the strain rate.…”

Section: Dislocation Mobilitysupporting

confidence: 92%

A micromechanical model of hardening, rate sensitivity and thermal softening in BCC single crystals

Stainier

Cuitiño

Ortiz

2002

Journal of the Mechanics and Physics of Solids

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The present paper is concerned with the development of a micromechanical model of the hardening, rate-sensitivity and thermal softening of bcc crystals. In formulating the model, we speciÿcally consider the following unit processes: double-kink formation and thermally activated motion of kinks; the close-range interactions between primary and forest dislocations, leading to the formation of jogs; the percolation motion of dislocations through a random array of forest dislocations introducing short-range obstacles of di erent strengths; dislocation multiplication due to breeding by double cross-slip; and dislocation pair annihilation. The model is found to capture salient features of the behavior of Ta crystals such as: the dependence of the initial yield point on temperature and strain rate; the presence of a marked stage I of easy glide, specially at low temperatures and high strain rates; the sharp onset of stage II hardening and its tendency to shift towards lower strains, and eventually disappear, as the temperature increases or the strain rate decreases; the parabolic stage II hardening at low strain rates or high temperatures; the stage II softening at high strain rates or low temperatures; the trend towards saturation at high strains; the temperature and strain-rate dependence of the saturation stress; and the orientation dependence of the hardening rate.

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Section: Dislocation Mobilitysupporting

confidence: 92%

A micromechanical model of hardening, rate sensitivity and thermal softening in BCC single crystals

Stainier

Cuitiño

Ortiz

2002

Journal of the Mechanics and Physics of Solids

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“…The Peierls stress decreases ostensibly linearly up to a critical temperature T c , beyond which it tends to zero. These trends are in agreement with the experimental observations of Wasserbäch [22] and Lachenmann and Schultz [23]. The critical temperature T c increases with the strain rate.…”

Section: Dislocation Mobility: Double-kink Formation and Thermally Acsupporting

confidence: 92%

Untitled

Cuitiño

Stainier

Wang

et al. 2001

Journal of Computer-Aided Materials Design

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In this paper we present a modeling approach to bridge the atomistic with macroscopic scales in crystalline materials. The methodology combines identification and modeling of the controlling unit processes at microscopic level with the direct atomistic determination of fundamental material properties. These properties are computed using a many body Force Field derived from ab initio quantum-mechanical calculations. This approach is exercised to describe the mechanical response of high-purity Tantalum single crystals, including the effect of temperature and strain-rate on the hardening rate. The resulting atomistically informed model is found to capture salient features of the behavior of these crystals such as: the dependence of the initial yield point on temperature and strain rate; the presence of a marked stage I of easy glide, specially at low temperatures and high strain rates; the sharp onset of stage II hardening and its tendency to shift towards lower strains, and eventually disappear, as the temperature increases or the strain rate decreases; the parabolic stage II hardening at low strain rates or high temperatures; the stage II softening at high strain rates or low temperatures; the trend towards saturation at high strains; the temperature and strain-rate dependence of the saturation stress; and the orientation dependence of the hardening rate.

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“…With thermal fluctuations, these results did not change significantly, though at lowγ, which is where the change would be greatest, it was not possible to include fluctuations and maintain reasonable computation times. Similar linear decreases in γ P as some effective T c is approached have been found in experiment [16,17] and theory [18,19], along with increases in γ P withγ much like those shown in Fig. 6.…”

Section: Peierls Barrier For Glidesupporting

confidence: 86%

Diffusive atomistic dynamics of edge dislocations in two dimensions

2006

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The fundamental dislocation processes of glide, climb, and annihilation are studied on diffusive time scales within the framework of a continuum field theory, the phase field crystal model. Glide and climb are examined for single edge dislocations subjected to shear and compressive strain, respectively, in a two-dimensional hexagonal lattice. It is shown that the natural features of these processes are reproduced without any explicit consideration of elasticity theory or ad hoc construction of microscopic Peierls potentials. Particular attention is paid to the Peierls barrier for dislocation glide or climb and the ensuing dynamic behavior as functions of strain rate, temperature, and dislocation density. It is shown that the dynamics are accurately described by simple viscous motion equations for an overdamped point mass, where the dislocation mobility is the only adjustable parameter. The critical distance for the annihilation of two edge dislocations as a function of separation angle is also presented.

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Inherent lattice hardening and interstitial solution hardening in tantalum

Cited by 44 publications

References 24 publications

A micromechanical model of hardening, rate sensitivity and thermal softening in BCC single crystals

A micromechanical model of hardening, rate sensitivity and thermal softening in BCC single crystals

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Diffusive atomistic dynamics of edge dislocations in two dimensions

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