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Title: Mechanism and modeling of saw-tooth structure formation in the L1{sub 2}-L1{sub 0} two-phase system

Abstract

The strain-accommodating mechanism of formation of the saw-tooth microstructure in the LI{sub 2} + LI{sub 0} two-phase ordered system is proposed. To describe the atomic scale kinetics of ordering and decomposition in this system, the master equation, which explicitly incorporates the effect of the transformation strain, is formulated. It is used to simulate the precipitation of the LI{sub 0} phase from the LI{sub 2} parent phase in the Co-Pt alloy. The computer simulation shows that the decomposition occurs heterogeneously on antiphase boundaries of the LI{sub 2} structure if the composition is near the solubility limit of the LI{sub 2} phase. It eventually produces the saw-tooth microstructure. The decomposition transforms the (010) anti-phase boundary into a layer of the single-variant tetragonal LI{sub 0} phase separating the LI{sub 2} antiphase domains. Later, the strain accommodation transforms this single-variant LI{sub 0} phase layer into the saw-tooth pattern. The simulation results are in excellent qualitative and quantitative agreement with out TEM images of Co{sub 38.5}Pt{sub 61.5}.

Authors:
;
Publication Date:
Research Org.:
Rutgers Univ., Piscataway, NJ (US)
OSTI Identifier:
20075927
Resource Type:
Journal Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 48; Journal Issue: 8; Other Information: PBD: 11 May 2000; Journal ID: ISSN 1359-6454
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MICROSTRUCTURE; ELASTICITY; COBALT ALLOYS; PLATINUM ALLOYS; COMPUTERIZED SIMULATION; PHASE STUDIES; KINETICS; CRYSTAL-PHASE TRANSFORMATIONS

Citation Formats

Le Bouar, Y., and Khachaturyan, A.G. Mechanism and modeling of saw-tooth structure formation in the L1{sub 2}-L1{sub 0} two-phase system. United States: N. p., 2000. Web. doi:10.1016/S1359-6454(00)00017-3.
Le Bouar, Y., & Khachaturyan, A.G. Mechanism and modeling of saw-tooth structure formation in the L1{sub 2}-L1{sub 0} two-phase system. United States. doi:10.1016/S1359-6454(00)00017-3.
Le Bouar, Y., and Khachaturyan, A.G. Thu . "Mechanism and modeling of saw-tooth structure formation in the L1{sub 2}-L1{sub 0} two-phase system". United States. doi:10.1016/S1359-6454(00)00017-3.
@article{osti_20075927,
title = {Mechanism and modeling of saw-tooth structure formation in the L1{sub 2}-L1{sub 0} two-phase system},
author = {Le Bouar, Y. and Khachaturyan, A.G.},
abstractNote = {The strain-accommodating mechanism of formation of the saw-tooth microstructure in the LI{sub 2} + LI{sub 0} two-phase ordered system is proposed. To describe the atomic scale kinetics of ordering and decomposition in this system, the master equation, which explicitly incorporates the effect of the transformation strain, is formulated. It is used to simulate the precipitation of the LI{sub 0} phase from the LI{sub 2} parent phase in the Co-Pt alloy. The computer simulation shows that the decomposition occurs heterogeneously on antiphase boundaries of the LI{sub 2} structure if the composition is near the solubility limit of the LI{sub 2} phase. It eventually produces the saw-tooth microstructure. The decomposition transforms the (010) anti-phase boundary into a layer of the single-variant tetragonal LI{sub 0} phase separating the LI{sub 2} antiphase domains. Later, the strain accommodation transforms this single-variant LI{sub 0} phase layer into the saw-tooth pattern. The simulation results are in excellent qualitative and quantitative agreement with out TEM images of Co{sub 38.5}Pt{sub 61.5}.},
doi = {10.1016/S1359-6454(00)00017-3},
journal = {Acta Materialia},
issn = {1359-6454},
number = 8,
volume = 48,
place = {United States},
year = {2000},
month = {5}
}