Dislocation nucleation from a crack tip: A formulation based on anisotropic elasticity

Sun, Yuemin; Beltz, Glenn E.

doi:10.1016/0022-5096(94)90018-3

Cited by 61 publications

(52 citation statements)

References 23 publications

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“…With h $ unity, [31] one finds with the theoretical g us that the values of K t are somewhat smaller than the Griffith fracture value for the shuffle set dislocations. Similarly, along with the unstable stacking fault energy results determined by finite temperature dynamics modeling of silicon, [30] one also finds a stress intensity value for dislocation nucleation to be about 30 percent smaller under zero pressure at room temperature in the shuffle set compared to the glide set.…”

Section: Brittle-to-ductile Transistionmentioning

confidence: 91%

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Brittle‐to‐Ductile Transition in Uniaxial Compression of Silicon Pillars at Room Temperature

Östlund

Rzepiejewska-Malyska

Leifer

et al. 2009

Adv Funct Materials

274

163

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Robust nanostructures for future devices will depend increasingly on their reliability. While great strides have been achieved for precisely evaluating electronic, magnetic, photonic, elasticity and strength properties, the same levels for fracture resistance have been lacking. Additionally, one of the self‐limiting features of materials by computational design is the knowledge that the atomistic potential is an appropriate one. A key property in establishing both of these goals is an experimentally‐determined effective surface energy or the work per unit fracture area. The difficulty with this property, which depends on extended defects such as dislocations, is measuring it accurately at the sub‐micrometer scale. In this Full Paper the discovery of an interesting size effect in compression tests on silicon pillars with sub‐micrometer diameters is presented: in uniaxial compression tests, pillars having a diameter exceeding a critical value develop cracks, whereas smaller pillars show ductility comparable to that of metals. The critical diameter is between 310 and 400 nm. To explain this transition a model based on dislocation shielding is proposed. For the first time, a quantitative method for evaluating the fracture toughness of such nanostructures is developed. This leads to the ability to propose plausible mechanisms for dislocation‐mediated fracture behavior in such small volumes.

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Section: Brittle-to-ductile Transistionmentioning

confidence: 91%

“…From Sun and Beltz, [31] the effective stress intensity for dislocation nucleation under shear is given by…”

Section: Brittle-to-ductile Transistionmentioning

confidence: 99%

Brittle‐to‐Ductile Transition in Uniaxial Compression of Silicon Pillars at Room Temperature

Östlund

Rzepiejewska-Malyska

Leifer

et al. 2009

Adv Funct Materials

274

163

View full text Add to dashboard Cite

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“…The critical stress intensity factor for dislocation nucleation from the crack tip can be computed based on the theory of Rice [2] extended to anisotropic elasticity by Sun et al [15] as…”

Section: Cracks In Anisotropic Linear Elastic Mediamentioning

confidence: 99%

Brittle and ductile crack-tip behavior in magnesium

Curtin

2015

Acta Materialia

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“…It decreases the stress barier for dislocation emission on {110} planes at temperature of 0 K by about 1 GPa to τ c = 13.5 GPa. As follows from [22], further reduction of the critical loading by about (10-15)% is expected due to the tension-shear coupling, i.e. due to a small normal relaxation in the slip systems during the dislocation emission.…”

Section: Resultsmentioning

confidence: 95%

“…The basic elastic constants for the used potential at the basic cubic orientation are C 11 = 243 GPa, C 12 = 145 GPa, C 44 = 116 GPa. The needed constants A ij for the plane strain are A22 = A 11 = 0.639 × 10 −11 m 2 /N, A 12 = −0.3812 × 10 −11 m 2 /N, A 66 = 0.8621 × 10 −11 m 2 /N.The appropriate[19] conjugate pair of roots is:µ 1 = 0.6789502 + 0.7341481 i, µ 2 = −0.6789502 + 0.7341481 i. If we abbreviate the expressions for the stress components (1) by a general relation σ ij (θ) = K I √ 2πr g ij (µ 1 , µ 2 , θ), then the individual g-functions offer information about stress intensity at crack front in the different slip planes {110} and {112}.…”

mentioning

confidence: 99%

Brittle-ductile behavior in 3D iron crystals

et al. 2005

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We present large scale molecular dynamic (MD) simulations in bcc iron containing a relatively long Griffith crack loaded in mode I at a temperature of 0 K and 300 K. We use N-body potentials of Finnis-Sinclair type. The paper also includes a stress analysis performed in the framework of anisotropic fracture mechanics and on the atomic level as well. It enables us to understand why at 0 K brittle fracture in MD is detected, while at 300 K ductile behavior at the crack front in MD is monitored, starting from the free sample surface.

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Dislocation nucleation from a crack tip: A formulation based on anisotropic elasticity

Cited by 61 publications

References 23 publications

Brittle‐to‐Ductile Transition in Uniaxial Compression of Silicon Pillars at Room Temperature

Brittle‐to‐Ductile Transition in Uniaxial Compression of Silicon Pillars at Room Temperature

Brittle and ductile crack-tip behavior in magnesium

Brittle-ductile behavior in 3D iron crystals

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