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in subjects: "Grain Boundaries"  
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Including dislocation flux in a continuum crystal plasticity model to produce size scale effects

Description: A novel model has been developed to capture size scale and gradient effects within the context of continuum crystal plasticity by explicitly incorporating details of dislocation transport, coupling dislocation transport to slip, evolving spatial distributions of dislocations consistent with the flux, and capturing the interactions among various dislocation populations. Dislocation flux and density are treated as nodal degrees of freedom in the finite element model, and they are determined as pa… more
Date: February 13, 2004
Creator: Becker, R.; Arsenlis, A.; Bulatov, V. V. & Parks, D. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Elastic properties of supported polycrystalline thin films and multilayers: An X-ray diffraction study

Description: Numerous experimental and theoretical studies have shown that thin film elastic behavior may be different from the bulk one due to size effects related to grain boundaries, free surfaces and interfaces. In addition, thin films often present high compressive residual stresses which may be responsible of thin film buckling. These two features will be discussed in this communication through recent x-ray diffraction experiments: in situ tensile testing for elastic constant analysis and scanning x-r… more
Date: August 13, 2003
Creator: Goudeau, P.; Villain, P.; Tamura, N.; Renault, P.-O.; Badawi, K.F. & Padmore, H.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

UNDERSTANDING THE MECHANISMS CONTROLLING ENVIRONMENTALLY-ASSISTED INTERGRANULAR CRACKING OF NICKEL-BASE ALLOYS

Description: Creep and IG cracking of nickel-base alloys depend principally on two factors--the deformation behavior and the effect of the environment. We have shown that both contribute to the observed degradation in primary water. The understanding of cracking does not lie wholly within the environmental effects arena, nor can it be explained only by intrinsic mechanical behavior. Rather, both processes contribute to the observed behavior in primary water. In this project, we had three objectives: (1) to … more
Date: February 13, 2004
Creator: Was, Gary S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Residual Stress Predictions in Polycrystalline Alumina

Description: Microstructure-level residual stresses arise in polycrystalline ceramics during processing as a result of thermal expansion anisotropy and crystallographic disorientation across the grain boundaries. Depending upon the grain size, the magnitude of these stresses can be sufficiently high to cause spontaneous microcracking during the processing of these materials. They are also likely to affect where cracks initiate and propagate under macroscopic loading. The magnitudes of residual stresses in u… more
Date: December 13, 1999
Creator: VEDULA,VENKATA R.; GLASS,S. JILL; SAYLOR,DAVID M.; ROHRER,GREGORY S.; CARTER,W. CRAIG & LANGER,STEPHEN A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

CORROSION OF NICKEL-BASE SPECIMENS EXPOSED IN THE VOLATILITY PILOT PLANT MARK III FLUORINATOR

Description: The combination of operating temperatures around 550 deg C with LiF present in the salt baths produces about the same bulk metal losses on Ni and Ni- base alloys as was found by operating at 650 deg C without Li in the salt baths. The presence of U accelerates corrosion of Ni and Ni-base alloys during the Volatility Process fluorination cycle. Prior F conditioning of L Ni decreases corrosion of the material during subsequent fluorination. Prior F conditioning of INCO-61 weld metal increases the… more
Date: November 13, 1962
Creator: Kegley, T. M., Jr. & Litman, A. P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Energetics of Nanomaterials

Description: This project, ''Energetics of Nanomaterials'', represents a three-year collaboration among Alexandra Navrotsky (University of California at Davis), Brian Woodfield and Juliana Boerio-Goates (Brigham Young University) and Frances Hellman (University of California at San Diego). Its purpose has been to explore the differences between bulk materials, nanoparticles, and thin films in terms of their thermodynamic properties, with an emphasis on heat capacities and entropies, as well as enthalpies. W… more
Date: December 13, 2004
Creator: Hellman, Frances
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Novel thermal properties of nanostructured materials.

Description: A new class of heat transfer fluids, termed nanofluids, has been developed by suspending nanocrystalline particles in liquids. Due to the orders-of-magnitude larger thermal conductivities of solids compared to those of liquids such as water, significantly enhanced thermal properties are obtained with nanofluids. For example, an approximately 20% improvement in effective thermal conductivity is observed when 5 vol.% CuO nanoparticles are added to water. Even more importantly, the heat transfer c… more
Date: January 13, 1999
Creator: Eastman, J. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Grain-size-dependent thermal transport properties in nanophase yttria-stabilized zirconia.

Description: Understanding the role of grain boundaries in controlling heat flow is critical to the success of many envisioned applications of nanocrystalline materials. This study focuses on the effect of grain boundaries on thermal transport behavior in nanocrystalline yttria-stabilized zirconia (YSZ) coatings prepared by metal-organic chemical vapor deposition. A strong grain-size-dependent reduction in thermal conductivity is observed at all temperatures from 6-480 K. The behavior is due primarily to th… more
Date: December 13, 2001
Creator: Yang, H.-S.; Eastman, J. A.; Thompson, L. J. & Bai, G.-R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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