Theory of nonequilibrium segregation in an Fe-Mn-Ni ternary alloy and a ductile-brittle-ductile transition

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Acta Materialia

DOI:https://doi.org/10.1016/1359-6454(95)00355-X· OSTI ID:264116

Heo, N H ^[1]

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1. Massachusetts Inst. of Technology, Cambridge, MA (United States). Dept. of Materials Science and Engineering

In an Fe-8Mn-7Ni ternary alloy, age-hardened by coherently formed face-centered tetragonal MnNi intermetallic compounds within the matrix, a modeling based on a regular solution model is performed to formulate the nonequilibrium grain boundary segregation behaviors of the alloying elements, followed by a ductile-brittle-ductile transition in the alloy. An equation is derived representing the segregation kinetics. It is confirmed from the calculations that the segregation behaviors of the elements are directly controlled by the precipitation reaction in the matrix. The nonequilibrium segregation behaviors are characterized by time-temperature diagrams, which show maximum segregation levels of the elements in an intermediate aging time and temperature range. The calculated results explain theoretically and semiquantitatively the relationship between the nonequilibrium segregation of the elements and the ductile-brittle-ductile transition.

• Sponsoring Organization: USDOE
• OSTI ID: 264116
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 7 Vol. 44; ISSN XZ504Y; ISSN 1359-6454
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AGE HARDENING
BRITTLE-DUCTILE TRANSITIONS
DUCTILE-BRITTLE TRANSITIONS
GRAIN BOUNDARIES
INTERMETALLIC COMPOUNDS
IRON ALLOYS
KINETICS
MANGANESE ALLOYS
MATHEMATICAL MODELS
NICKEL
PRECIPITATION
SEGREGATION
TEMPERATURE DEPENDENCE
TIME DEPENDENCE