Journal ArticleDOI
The threshold stress for creep controlled by dislocation-particle interaction
TLDR
In this article, a model based on the dissociation of lattice dislocations into interfacial dislocation was proposed to explain the attractive dislocation-particle interaction during the creep of dispersion-strengthened alloys.Abstract:
A model based on the dissociation of lattice dislocations into interfacial dislocations, when they enter the matrix-particle interface for climb bypass, is proposed to explain the attractive dislocation-particle interaction during the creep of dispersion-strengthened alloys. This model predicts a threshold stress for creep which depends on the particle radius, the interparticle spacing and the reduction in dislocation self-energy because of dissociation. A minimum energy reduction of about 36% is required through the dissociation to offset the increase in line length energy because of the local climb configuration. There is reasonable agreement between theoretical predictions and experimental data on threshold stresses. The model is also supported by transmission electron microscopy evidence of departure-side pinning and contrast at the matrix-particle interface.read more
Citations
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Journal ArticleDOI
Review of recent studies in magnesium matrix composites
Hai Zhi Ye,Xing Yang Liu +1 more
TL;DR: In this article, the conventional and new processes for the fabrication of magnesium matrix composites are summarized and the composite microstructure is subsequently discussed with respect to grain refinement, reinforcement distribution, and interfacial characteristics.
Journal ArticleDOI
An examination of the constitutive equation for elevated temperature plasticity
TL;DR: The constitutive relation that links the stress-strain rate-grain size-temperature relation (Mukherjee-Bird-Dorn, MBD correlation) was presented in 1968/1969 to describe the elevated temperature crystalline plasticity has held up well during the intervening quarter of a century.
Journal ArticleDOI
Creep deformation mechanisms in modified 9Cr–1Mo steel
Triratna Shrestha,Mehdi Basirat,Indrajit Charit,Gabriel P. Potirniche,Karl K. Rink,Uttara Sahaym +5 more
TL;DR: In this paper, the tensile creep behavior of modified 9Cr-1Mo steel (Grade 91) was studied in the temperature range of 873 − 1023 K and stresses between 35 − MPa and 350 −MPa.
Journal ArticleDOI
Interface controlled plasticity in metals: dispersion hardening and thin film deformation
TL;DR: In this article, the authors focus on two modern aspects of fundamental and practical interest: the mechanism of dispersion hardening at high temperatures, which allows the design of alloys operating close to their melting point; and the constraints on dislocation and diffusional deformation processes in metallic thin films, a potential reliability problem for micro-systems subjected to high internal stresses.
Journal ArticleDOI
Model for creep threshold stress in precipitation-strengthened alloys with coherent particles
TL;DR: In this article, the general climb model for creep threshold stress for dislocations interacting with incoherent particles is modified for the case of coherent precipitates, by taking into account elastic interactions between matrix dislocation and particles due to particle/matrix stiffness and lattice mismatches.
References
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Journal ArticleDOI
Threshold stresses for dislocation climb over hard particles: The effect of an attractive interaction
Eduard Arzt,David Wilkinson +1 more
TL;DR: In this paper, the authors present a model for the effect of an attractive interaction between dislocations and hard spherical particles on the process of dislocation bypass by local climb, treating the interaction by assigning a line tension to the dislocation which is lower in the vicinity of the particle than in the matrix.
Journal ArticleDOI
High temperature creep of Ni-20Cr-2ThO2 single crystals
R.W. Lund,William D. Nix +1 more
TL;DR: The high temperature creep properties of single crystals of Ni-20Cr-2ThO 2 have been investigated in the temperature range 650-1300°C in this article, where single crystal tensile specimens were cut from plates having a large elongated grain structure and constant stress vacuum creep tests were conducted at various stresses and temperatures.
Journal ArticleDOI
TEM in situ deformation study of the interaction of lattice dislocations with grain boundaries in metals
TL;DR: In this article, a detailed analysis of the interaction of glissile matrix dislocations with grain-boundary dislocation has been performed by using in situ TEM deformation technique.
Journal ArticleDOI
High-temperature strength of dispersion-hardened single crystals II. Theory
R. S. W. Shewfelt,L. M. Brown +1 more
TL;DR: In this article, a theory of the yield stress of dispersion-hardened single crystals as a function of temperature and strain rate is described, and a computer program which simulates a dislocation going through a random array of point obstacles some of which are by-passed by climb is described.
Journal ArticleDOI
On the absorption of dislocations by grain boundaries
R. C. Pond,David Smith +1 more
TL;DR: In this article, the absorption process is extended to random boundaries with the help of a new model for their structure in which the existence of an irregular arrangement of certain low energy groups of atoms is postulated.
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