Mechanism and modeling of saw-tooth structure formation in the L1{sub 2}-L1{sub 0} two-phase system
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}.
- Research Organization:
- Rutgers Univ., Piscataway, NJ (US)
- OSTI ID:
- 20075927
- Journal Information:
- Acta Materialia, Vol. 48, Issue 8; Other Information: PBD: 11 May 2000; ISSN 1359-6454
- Country of Publication:
- United States
- Language:
- English
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