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A Novel Microcharacterization Technique in the Measurement of Strain and Orientation Gradient in Advanced MaterialsRepresentation of morphology and evolution of the microstructure during processing and their relation to properties requires proper experimental techniques. Residual strains, lattice distortion, and texture (micro-texture) at the interface and the matrix of a layered structure or a functionally gradient material and their variation are among parameters important in materials characterization but hard to measure with present experimental techniques. Current techniques available to measure changes in interred material parameters (residual stress, micro-texture, microplasticity) produce results which are either qualitative or unreliable. This problem becomes even more complicated in the case of a temperature variation. These parameters affect many of the mechanical properties of advanced materials including stress-strain relation, ductility, creep, and fatigue. A review of some novel experimental techniques using recent advances in electron microscopy is presented here to measure internal stress, (micro)texture, interracial strength and (sub)grain formation and realignment. Two of these techniques are combined in the chamber of an Environmental Scanning Electron Microscope to measure strain and orientation gradients in advanced materials. These techniques which include Backscattered Kikuchi Diffractometry (BKD) and Microscopic Strain Field Analysis are used to characterize metallic and intermetallic matrix composites and superplastic materials. These techniques are compared with the more conventional x-ray diffraction and indentation techniques.
Document ID
20010000516
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Garmestai, H.
(Florida Agricultural and Mechanical Univ. Tallahassee, FL United States)
Harris, K.
(Florida State Univ. Tallahassee, FL United States)
Lourenco, L.
(Florida Agricultural and Mechanical Univ. Tallahassee, FL United States)
Date Acquired
August 20, 2013
Publication Date
February 1, 1997
Publication Information
Publication: NASA University Research Centers Technical Advances in Education, Aeronautics, Space, Autonomy, Earth and Environment
Volume: 1
Subject Category
Structural Mechanics
Report/Patent Number
URC97158
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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