Numerical analysis of dissolution of [alpha] phase in [gamma]/[alpha]/[gamma] diffusion couples of the Fe-Cr-Ni system

Journal Article · Thu Jul 01 00:00:00 EDT 1993 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(93)90374-2· OSTI ID:6327916

Kajihara, M; Kikuchi, M ^[1]

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1. Tokyo Inst. of Tech., Tokyo (Japan). Dept. of Metallurgical Engineering

The dissolution kinetics of body-centered-cubic (b.c.c.) [alpha]-ferrite in face-centered-cubic (f.c.c.) [gamma]-austenite matrix was experimentally studied by the present authors at 1,373 K using four sets of [gamma]/[alpha]/[gamma] diffusion couples of the ternary Fe-Cr-Ni system. In the present study, the experimental results have been numerically analyzed using a computer calculation technique on the basis of the following assumptions: (a) the reaction is diffusion controlled, (b) the interdiffusion coefficients in each phase are independent of the composition, (c) the coupled-diffusion between chromium and nickel is negligible, and (d) the molar volumes of the [alpha] and [gamma] phases are the same. Though the [alpha] phase should completely disappear to dissolve in the [gamma] phase after sufficiently long annealing, the thickness of the [alpha] phase increases with increasing annealing time at an early stage of the reaction. After reaching a maximum value, the thickness of the [alpha] phase decreases with increasing annealing time. The composition of the moving [alpha]/[gamma] interface changes with annealing time once diffusion zones start to overlap in the [alpha] phase. These characteristics could be quantitatively reproduced by the numerical calculation. Furthermore, the calculation predicted that at a very early stage of the reaction the interface composition might change with increasing annealing time toward the opposite direction to the one observed in the later stage.

• OSTI ID: 6327916
• Journal Information: Acta Metallurgica et Materialia; (United States), Vol. 41:7; ISSN 0956-7151
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM-NICKEL STEELS
PHASE STUDIES
ANNEALING
AUSTENITE
BCC LATTICES
COMPUTER CALCULATIONS
DIFFUSION
DISSOLUTION
FCC LATTICES
FERRITE
NUMERICAL ANALYSIS
PHASE DIAGRAMS
TEMPERATURE RANGE 1000-4000 K
TERNARY ALLOY SYSTEMS
THEORETICAL DATA
ALLOY SYSTEMS
ALLOYS
CARBON ADDITIONS
CHROMIUM ALLOYS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CUBIC LATTICES
DATA
DIAGRAMS
HEAT TREATMENTS
HIGH ALLOY STEELS
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
MATHEMATICS
NICKEL ALLOYS
NUMERICAL DATA
STAINLESS STEELS
STEELS
TEMPERATURE RANGE
360102* - Metals & Alloys- Structure & Phase Studies