SEARCH · Search NASA
Results for “DISLOCATION”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Dislocation loop evolution in F/M steel T91 under in-situ ion irradiation: Influence of the presence of initial dislocations
Ferritic/Martensitic (F/M) steel T91 was irradiated in-situ to 4 and 10 dpa at 470 °C using 1 MeV Kr 2+ . Additionally, the microstructure evolution under irradiation was followed and characterized by in-situ Transmission Electron Microscopy (TEM), in terms of dislocation loop Burgers vector, average size and density as a function of dose. Furthermore, the influence of the presence of dislocations in the pre-irradiated matrix was investigated by comparing the radiation induced defect evolution in grains with and without initial dislocations.
Dislocation interactions in olivine control postseismic creep of the upper mantle
Changes in stress applied to mantle rocks, such as those imposed by earthquakes, commonly induce a period of transient creep, which is often modelled based on stress transfer among slip systems due to grain interactions. However, recent experiments have demonstrated that the accumulation of stresses among dislocations is the dominant cause of strain hardening in olivine at temperatures ≤600 °C, raising the question of whether the same process contributes to transient creep at higher temperatures. Here, we demonstrate that olivine samples deformed at 25 °C or 1150–1250 °C both preserve stress heterogeneities of ~1 GPa that are imparted by dislocations and have correlation lengths of ~1 μm. The similar stress distributions formed at these different temperatures indicate that accumulation of stresses among dislocations also provides a contribution to transient creep at high temperatures. The results motivate a new generation of models that capture these intragranular processes and may refine predictions of evolving mantle viscosity over the earthquake cycle.
Dislocation glide suppression for misfit dislocation free heteroepitaxy
An epitaxial structure includes a semiconductor substrate, a dislocation blocking layer; and one or more active layers.
Phase field dislocation dynamics formulation coupled with Fourier based micromechanics solver: Application to grain boundary-dislocation interactions
Explore the source record for details and available documents.
Dislocation density distribution at slip band-grain boundary intersections
Abstract not provided
Ultra-high strength and plasticity mediated by partial dislocations and defect networks: Part I: Texture effect
Not provided.
Atomistic simulations of dislocation activity in Si nanofibers in Al-Si eutectics
Not provided.
Synchrotron X-ray topographic characterization of dislocations in 6H-SiC axial samples
Not Available
Prediction of yield surface of single crystal copper from discrete dislocation dynamics and geometric learning
Not provided.
Interplay of dislocation substructure and elastic strain evolution in additively manufactured Inconel 625
Not provided.
Interplay between dislocation type and local structure in dislocation-twin boundary reactions in Cu
Not Available
Discrete dislocation dynamics-based prediction of dislocation density from diffraction line profiles of Ta
Explore the source record for details and available documents.