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Title: Elastic Behavior and Strength of Al2O3 Fiber/Al Matrix Composite and Implications for Equation of State Measurements in the Diamond Anvil Cell

Abstract

To examine pressure relationships in a mixed phase assemblage, we performed room temperature/high pressure radial x-ray diffraction measurements on a controlled-geometry bimaterial composite consisting of oriented Al{sub 2}O{sub 3} fibers embedded in an aluminum matrix. Lattice strains of each material were measured as a function of orientation with respect to the fiber alignment, as a function of orientation with respect to the major principal stress axis of the diamond cell, and as a function of pressure of up to 15 GPa. The results show that Al and Al{sub 2}O{sub 3} both support differential stresses, with Al supporting between -0.06(45) and 0.32(65) GPa and Al{sub 2}O{sub 3} supporting between 1.4(3) and 4.9(9) GPa. The hydrostatic pressures determined from the average lattice strains of Al and Al{sub 2}O{sub 3} are not in general equal, with the pressure of Al{sub 2}O{sub 3} higher than that of Al by an average of 0.5(4) GPa throughout the measured range. The geometric relationship between the composite material and the principal stress axis of the diamond cell plays a role in establishing both the absolute and relative strain responses of the composite sample. A comparison of the two composite geometries under the same diamond cell compression showsmore » that when the fibers are oriented vertically along the diamond cell axis, the differential stress supported by Al{sub 2}O{sub 3} is 3.1(5) GPa, at a pressure of 9.35(42) GPa. The corresponding values for Al are much lower: 0.09(18) GPa (differential stress) and 8.67(04) GPa (hydrostatic pressure). When the fibers are oriented horizontally along the radial direction, the pressure supported by Al and Al{sub 2}O{sub 3} is more similar: 9.63(15) vs 9.48(35) GPa. The differential stress supported by both materials is higher: 0.32(65) for Al and 4.9(9) for Al{sub 2}O{sub 3}. Understanding the strength and elastic behavior of an intermixed phase assemblage is vital for the interpretation of mineral behavior at high pressures and temperatures. Many in situ measurements of high pressure mineral phase stability and elasticity are performed using intermixed phases-the unknown and a reference marker. Measurement of properties relies on the assumptions that the reference material has an accurate and well-calibrated equation of state and that the pressures of the two materials are identical in the high pressure sample chamber. This latter assumption is clearly violated in our experiments. Therefore, it is important to account for potential pressure effects due to sample geometry when making in situ x-ray measurements of equations of state and phase transformations.« less

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930571
Report Number(s):
BNL-80751-2008-JA
Journal ID: ISSN 0021-8979; JAPIAU; TRN: US200904%%791
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 100; Journal Issue: 4
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALIGNMENT; ALUMINIUM; AMBIENT TEMPERATURE; COMPOSITE MATERIALS; COMPRESSION; DIAMONDS; ELASTICITY; EQUATIONS OF STATE; FIBERS; GEOMETRY; HYDROSTATICS; ORIENTATION; PHASE STABILITY; PHASE TRANSFORMATIONS; PRESSURE DEPENDENCE; PRESSURE RANGE GIGA PA; STRAINS; STRESSES; X-RAY DIFFRACTION; national synchrotron light source

Citation Formats

Conil,N., and Kavner, A. Elastic Behavior and Strength of Al2O3 Fiber/Al Matrix Composite and Implications for Equation of State Measurements in the Diamond Anvil Cell. United States: N. p., 2006. Web. doi:10.1063/1.2234556.
Conil,N., & Kavner, A. Elastic Behavior and Strength of Al2O3 Fiber/Al Matrix Composite and Implications for Equation of State Measurements in the Diamond Anvil Cell. United States. doi:10.1063/1.2234556.
Conil,N., and Kavner, A. Sun . "Elastic Behavior and Strength of Al2O3 Fiber/Al Matrix Composite and Implications for Equation of State Measurements in the Diamond Anvil Cell". United States. doi:10.1063/1.2234556.
@article{osti_930571,
title = {Elastic Behavior and Strength of Al2O3 Fiber/Al Matrix Composite and Implications for Equation of State Measurements in the Diamond Anvil Cell},
author = {Conil,N. and Kavner, A.},
abstractNote = {To examine pressure relationships in a mixed phase assemblage, we performed room temperature/high pressure radial x-ray diffraction measurements on a controlled-geometry bimaterial composite consisting of oriented Al{sub 2}O{sub 3} fibers embedded in an aluminum matrix. Lattice strains of each material were measured as a function of orientation with respect to the fiber alignment, as a function of orientation with respect to the major principal stress axis of the diamond cell, and as a function of pressure of up to 15 GPa. The results show that Al and Al{sub 2}O{sub 3} both support differential stresses, with Al supporting between -0.06(45) and 0.32(65) GPa and Al{sub 2}O{sub 3} supporting between 1.4(3) and 4.9(9) GPa. The hydrostatic pressures determined from the average lattice strains of Al and Al{sub 2}O{sub 3} are not in general equal, with the pressure of Al{sub 2}O{sub 3} higher than that of Al by an average of 0.5(4) GPa throughout the measured range. The geometric relationship between the composite material and the principal stress axis of the diamond cell plays a role in establishing both the absolute and relative strain responses of the composite sample. A comparison of the two composite geometries under the same diamond cell compression shows that when the fibers are oriented vertically along the diamond cell axis, the differential stress supported by Al{sub 2}O{sub 3} is 3.1(5) GPa, at a pressure of 9.35(42) GPa. The corresponding values for Al are much lower: 0.09(18) GPa (differential stress) and 8.67(04) GPa (hydrostatic pressure). When the fibers are oriented horizontally along the radial direction, the pressure supported by Al and Al{sub 2}O{sub 3} is more similar: 9.63(15) vs 9.48(35) GPa. The differential stress supported by both materials is higher: 0.32(65) for Al and 4.9(9) for Al{sub 2}O{sub 3}. Understanding the strength and elastic behavior of an intermixed phase assemblage is vital for the interpretation of mineral behavior at high pressures and temperatures. Many in situ measurements of high pressure mineral phase stability and elasticity are performed using intermixed phases-the unknown and a reference marker. Measurement of properties relies on the assumptions that the reference material has an accurate and well-calibrated equation of state and that the pressures of the two materials are identical in the high pressure sample chamber. This latter assumption is clearly violated in our experiments. Therefore, it is important to account for potential pressure effects due to sample geometry when making in situ x-ray measurements of equations of state and phase transformations.},
doi = {10.1063/1.2234556},
journal = {Journal of Applied Physics},
number = 4,
volume = 100,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
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