Thermal stability of irradiation-induced point defects in cubic silicon carbide
This work aims specifically at studying the evolution of point defects induced by electron irradiation in the cubic polytype of SiC (3C-SiC) at temperatures ranging from 10 to 1450 K by means of photo...
This work aims specifically at studying the evolution of point defects induced by electron irradiation in the cubic polytype of SiC (3C-SiC) at temperatures ranging from 10 to 1450 K by means of photo...
X-ray diffraction study of aluminum carbide powder to 50 GPa
The crystal structure and equation of state (EOS) of aluminum carbide (Al4C3) have been determined directly up to 50.1 GPa at room temperature by the synchrotron x-ray diffraction techniques. The resu...
The crystal structure and equation of state (EOS) of aluminum carbide (Al4C3) have been determined directly up to 50.1 GPa at room temperature by the synchrotron x-ray diffraction techniques. The resu...
Dislocation-interaction-based model of strained-layer relaxation
J. Appl. Phys. 106, 083510 (2009); doi:10.1063/1.3243285
Published 22 October 2009
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A strained layer relaxes plastically when dislocations propagate within the layer, leaving behind an array of misfit dislocations at the layer interface. We develop an analytical model of this process, based on the idea that relaxation is frustrated when propagating dislocations are trapped or annihilated by encounters with previously created misfit dislocations or other propagating dislocations. The theory characterizes the evolving density of the misfit array and the density of propagating dislocations in terms of a pair of coupled rate equations. The two trapping functions which appear in these equations are evaluated quantitatively by numerically investigating all possible dislocation-dislocation encounters. Fluctuations in the local stress field driving the individual dislocations are explicitly taken into account when evaluating the trapping functions. Analysis of the rate equations shows that there are two regimes in the strain-relaxation dynamics. Initially, the strain decreases rapidly following a universal dependence on time scaled with the initial dislocation density n0. At a (rescaled) crossover time that increases with n0, the strain levels off from the universal relaxation curve and saturates to an asymptotic residual strain level, which decreases with n0. Microscopically, our model reveals that the initial fast strain-relaxation regime is dominated by collisions between propagating dislocations, while the slow saturation regime is dominated by the trapping of propagating dislocations by the misfits. In the end, the self-trapping of the propagating dislocations by the misfit array they themselves have generated leaves the layer in a frustrated state with residual strain higher than the critical strain. The predictions of the theory are found to be in good agreement with experimental measurements and with large-scale numerical simulations of layer relaxation.
©2009 American Institute of Physics
| History: | Received 26 May 2009; accepted 8 September 2009; published 22 October 2009 |
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http://link.aip.org/link/?JAPIAU/106/083510/1 |
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EPAPS
- layer_model_supp.pdf (101 kB) 22-Oct-2009 9:14
KEYWORDS and PACS
dislocation density,
dislocation interactions,
fluctuations,
internal stresses,
plasticity,
stress relaxation,
thin films
- 61.72.Bb
Theories and models of crystal defects - 61.72.Hh
Indirect evidence of dislocations and other defects - 81.40.Lm
Deformation, plasticity, and creep - 62.20.fq
Plasticity and superplasticity of solids - 68.60.Bs
Mechanical and acoustical properties of thin films - 68.35.Gy
Mechanical properties and surface strains of solid surfaces and interfaces - YEAR: 2009
RELATED DATABASES
PUBLICATION DATA
0021-8979 (print)
1089-7550 (online)
AIP
REFERENCES (32)
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