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Title: Thermal stability of L1 sub 2 structured Al sub 3 (Zr sub x V sub 1-x ) in rapidly solidified Al-Zr-V alloys

Abstract

The objective of this study was to investigate the stability of L1{sub 2} structured Al{sub 3} (Zr,V) precipitates in rapidly solidified Al-Zr-V alloys with respect to phase change and Ostwald ripening during thermal annealing and plastic deformation at elevated temperatures. The Al-5 vol.% Al{sub 3} (Zr{sub x}V{sub 1-x}) alloys, precipitation of the metastable L1{sub 2} phase is favored over the equilibrium phases, Al{sub 10} V and Al{sub 3}Zr (DO{sub 23}). The precipitation mechanism of the L1{sub 2} phase can be continuous or discontinuous. The former is favored by decreasing value of X or increasing the aging temperature as well. Coarsening of the spherical L1{sub 2} structured Al{sub 3}(Zr{sub .25}V{sub .75}) proceeds slowly at 425{degree}C. Based on a modified Lifshitz-Slyozov-Wagner theory for volume diffusion controlled coarsening, a reasonable precipitate/matrix interfacial energy of 20 mJ/m{sup 2} is obtained. The activation energy obtained from the particle coarsening is close to that for diffusivity of Zr in Al, suggesting volume diffusion of Zr is the rate controlling mechanisms of the Ostwald ripening of L1{sub 2} structured Al{sub 3}(Zr{sub .25}V{sub .75}) phase. Several structural faults present in Al{sub 10}V, DO{sub 23} structured Al{sub 3}Zr and the L1{sub 2} phases were identified with a high resolutionmore » electron microscope. An approach to alloy development for an improved Al-Zr-V base alloy is discussed based on the microstructures seen in several more concentrated Al-Zr-V alloys.« less

Authors:
Publication Date:
Research Org.:
Northwestern Univ., Evanston, IL (USA)
OSTI Identifier:
5182293
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ALLOYS; PHASE STUDIES; VANADIUM ALLOYS; ZIRCONIUM ALLOYS; DIFFUSION; MICROSTRUCTURE; STABILITY; ALLOYS; CRYSTAL STRUCTURE; 360102* - Metals & Alloys- Structure & Phase Studies

Citation Formats

Chen, Y C. Thermal stability of L1 sub 2 structured Al sub 3 (Zr sub x V sub 1-x ) in rapidly solidified Al-Zr-V alloys. United States: N. p., 1988. Web.
Chen, Y C. Thermal stability of L1 sub 2 structured Al sub 3 (Zr sub x V sub 1-x ) in rapidly solidified Al-Zr-V alloys. United States.
Chen, Y C. 1988. "Thermal stability of L1 sub 2 structured Al sub 3 (Zr sub x V sub 1-x ) in rapidly solidified Al-Zr-V alloys". United States.
@article{osti_5182293,
title = {Thermal stability of L1 sub 2 structured Al sub 3 (Zr sub x V sub 1-x ) in rapidly solidified Al-Zr-V alloys},
author = {Chen, Y C},
abstractNote = {The objective of this study was to investigate the stability of L1{sub 2} structured Al{sub 3} (Zr,V) precipitates in rapidly solidified Al-Zr-V alloys with respect to phase change and Ostwald ripening during thermal annealing and plastic deformation at elevated temperatures. The Al-5 vol.% Al{sub 3} (Zr{sub x}V{sub 1-x}) alloys, precipitation of the metastable L1{sub 2} phase is favored over the equilibrium phases, Al{sub 10} V and Al{sub 3}Zr (DO{sub 23}). The precipitation mechanism of the L1{sub 2} phase can be continuous or discontinuous. The former is favored by decreasing value of X or increasing the aging temperature as well. Coarsening of the spherical L1{sub 2} structured Al{sub 3}(Zr{sub .25}V{sub .75}) proceeds slowly at 425{degree}C. Based on a modified Lifshitz-Slyozov-Wagner theory for volume diffusion controlled coarsening, a reasonable precipitate/matrix interfacial energy of 20 mJ/m{sup 2} is obtained. The activation energy obtained from the particle coarsening is close to that for diffusivity of Zr in Al, suggesting volume diffusion of Zr is the rate controlling mechanisms of the Ostwald ripening of L1{sub 2} structured Al{sub 3}(Zr{sub .25}V{sub .75}) phase. Several structural faults present in Al{sub 10}V, DO{sub 23} structured Al{sub 3}Zr and the L1{sub 2} phases were identified with a high resolution electron microscope. An approach to alloy development for an improved Al-Zr-V base alloy is discussed based on the microstructures seen in several more concentrated Al-Zr-V alloys.},
doi = {},
url = {https://www.osti.gov/biblio/5182293}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1988},
month = {1}
}

Thesis/Dissertation:
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