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Title: Plastic deformation in oxide ceramics. Progress report, January 1-December 31, 1980

Abstract

Effects of O/U ratio on UO/sub 2/ single crystals oriented either to suppress or promote )100) < 110 > slip are described. For both orientations, a change from crystallographic to noncrystallographic slip is observed with composition and temperature and correlated with the presence of Willis defects. Research on the kinetics and mechanism of formation of crystallographic shear (CS) planes in reduced rutile (TiO/sub 2-x/) is also described. Two orientations of CS planes, )132) and )121), are present, although prior work had suggested that only one orientation would be present for the particular value of x studied. In-situ reductions in the environmental stage of the HVEM have also begun. Precipitation in nonstoichiometric spinels was also investigated.

Authors:
Publication Date:
Research Org.:
Case Western Reserve Univ., Cleveland, OH (USA). Dept. of Metallurgy and Materials Science
Sponsoring Org.:
USDOE
OSTI Identifier:
6880615
Alternate Identifier(s):
OSTI ID: 6880615
Report Number(s):
DOE/ER/04217-T1
TRN: 80-018722
DOE Contract Number:
AS02-77ER04217
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; RUTILE; MICROSTRUCTURE; SPINELS; PRECIPITATION; TITANIUM OXIDES; URANIUM DIOXIDE; SLIP; MONOCRYSTALS; ORIENTATION; QUANTITY RATIO; RESEARCH PROGRAMS; SHEAR; TEMPERATURE DEPENDENCE; ACTINIDE COMPOUNDS; ALKALINE EARTH METAL COMPOUNDS; ALUMINIUM COMPOUNDS; ALUMINIUM OXIDES; CHALCOGENIDES; CRYSTAL STRUCTURE; CRYSTALS; MAGNESIUM COMPOUNDS; MAGNESIUM OXIDES; MATERIALS; MINERALS; OXIDES; OXYGEN COMPOUNDS; RADIOACTIVE MATERIALS; RADIOACTIVE MINERALS; SEPARATION PROCESSES; TITANIUM COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; URANIUM COMPOUNDS; URANIUM OXIDES 360203* -- Ceramics, Cermets, & Refractories-- Mechanical Properties

Citation Formats

Heuer, A. H. Plastic deformation in oxide ceramics. Progress report, January 1-December 31, 1980. United States: N. p., 1980. Web. doi:10.2172/6880615.
Heuer, A. H. Plastic deformation in oxide ceramics. Progress report, January 1-December 31, 1980. United States. doi:10.2172/6880615.
Heuer, A. H. Mon . "Plastic deformation in oxide ceramics. Progress report, January 1-December 31, 1980". United States. doi:10.2172/6880615. https://www.osti.gov/servlets/purl/6880615.
@article{osti_6880615,
title = {Plastic deformation in oxide ceramics. Progress report, January 1-December 31, 1980},
author = {Heuer, A. H.},
abstractNote = {Effects of O/U ratio on UO/sub 2/ single crystals oriented either to suppress or promote )100) < 110 > slip are described. For both orientations, a change from crystallographic to noncrystallographic slip is observed with composition and temperature and correlated with the presence of Willis defects. Research on the kinetics and mechanism of formation of crystallographic shear (CS) planes in reduced rutile (TiO/sub 2-x/) is also described. Two orientations of CS planes, )132) and )121), are present, although prior work had suggested that only one orientation would be present for the particular value of x studied. In-situ reductions in the environmental stage of the HVEM have also begun. Precipitation in nonstoichiometric spinels was also investigated.},
doi = {10.2172/6880615},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 1980},
month = {Mon Sep 01 00:00:00 EDT 1980}
}

Technical Report:

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  • Research on plastic deformation in oxide ceramics has been undertaken. Specifically, the effects of non-stoichiometry on slip on the ''hard'' slip systems in Al-rich Mg--Al spinel and oxygen-rich UO/sub 2 + x/ single crystals is under investigation. In the case of spinel, dislocation structures in both stoichiometric and alumina-rich specimens deformed in compression at elevated temperatures (1500 to 1900/sup 0/C) have been studied using transmission electron microscopy. Unusual dislocation structures are observed after large plastic strains, which are attributed to extensive climb and unique node reactions are observed which are the result of climb dissociation. This climb dissociation is attributedmore » to the presence of large concentrations of vacancies produced by non-conservative dislocation motion.« less
  • The composition softening that occurs in non-stoichiometric Mg-Al spinel, precipitation of Al/sub 2/O/sub 3/ in these materials, and the softening that accompanies hyperstoichiometry in UO/sub 2 + x/ were studied. Non-stoichiometry in rutile (TiO/sub 2/), specifically the formation of crystallogaphic shear planes in reduced samples was investigated.
  • Research conducted during the last year on Microstructural Development in Oxide Ceramics is described. Our major efforts have been devoted to studies of the effects of non-stoichiometry on plastic deformation in Mg-Al spinel and in UO/sub 2+x/. The spinel work is now finished and is summarized. In UO/sub 2+x/ the effects of O/U ratio on UO/sub 2/ single crystals oriented either to suppress or promote (100)<110> slip are described. We have found that both (111)<110> and (110)<110> can occur; the former system is favored at low temperatures and high O/U ratios, and the CRSS for (111) glide decreases with increasingmore » O/U ratios.« less
  • Problems of cyclic creep and time-dependent cyclic deformation are being increasingly recognized in machines used for energy conversion and storage, but few studies have been done in exploration of the relevant damage phenomena. Accordingly, the proposal called for the parallel study of two kinds of damage produced in cyclic creep, i.e., change in dislocation density and arrangement, to be studied in copper and damage phenomena perhaps involving precipitates in Cr-Mo-V rotor steel. Although funding was not received until March 1980, progress in studying both types of damage has been encouraging. In copper tested at low temperatures, strain bursts have beenmore » recognized for the first time in polycrystals of a pure metal in both cyclic and static creep. The stress regime for producing bursts has been defined and the dislocation structures associated with them studied. Interpretation based on instabilities associated with the persistent slip bands which form in regular fatigue is being explored. For the study of rotor steel, three batches of material have been obtained and characterized and a new high temperature apparatus built to do tests. A literature review justifying the choice of steels and tests is provided.« less
  • Information is presented concerning pore migration in KCl crystals in a temperature gradient; thermomigration of electronic defects and vacancies in FeO; time-dependent thermomigration; influence of transmutation on radiotracer diffusion; study of local electrochemical equilibrium; and short-circuit diffusion paths.