Equilibrium solubility and composition of mixed carbonitrides in microalloyed austenite

Journal Article · Fri Oct 01 04:00:00 EDT 1993 · Acta Metallurgica et Materialia; (United States)

DOI:https://doi.org/10.1016/0956-7151(93)90114-8· OSTI ID:5993132

Houghton, D C ^[1]

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1. National Research Council of Canada, Ottawa, Ontario (Canada). Inst. for Microstructural Sciences

A thermodynamic framework is presented which treats the mixing of refractory metal carbides and nitrides, e.g. Ti, Nb and V which appear in microalloyed steels. The intermixing of metal solutes, carbon and nitrogen on a single precipitate crystal lattice is considered, using a quasi-regular solution model. Two extreme cases are considered; complete intermixing of all binary compounds to provide an upper limit for precipitate stability, and mutual immiscibility of binary compounds allowing only the simultaneous coprecipitation of carbides and nitrides. These extreme cases provide an upper and lower bound for carbonitride solubility. Specific examples are used to illustrate precipitation from austenite of a ternary carbonitride, NbC[sub y]N[sub 1[minus]y], the quaternary mixed carbonitrides Ti[sub x]Nb[sub 1[minus]x]C[sub y]N[sub 1[minus]y], Ti[sub x]V[sub 1[minus]x]C[sub y]N[sub 1[minus]y] and V[sub x]Nb[sub 1[minus]x]C[sub y]N[sub 1[minus]y] and the quinery nitride, Ti[sub x]Ta[sub y]Nb[sub z]V[sub 1[minus]x[minus]y[minus]z]N. The determination of solution parameters allow the computation of the multi-component phase diagram Fe- [Sigma][sub i]Mi [Sigma][sub j]X[sub j]. Finally, the time-temperature constraints or processing are briefly addressed by allowing limited precipitate intermixing, while maintaining equilibrium between solutes in austenite.

• OSTI ID: 5993132
• Journal Information: Acta Metallurgica et Materialia; (United States), Journal Name: Acta Metallurgica et Materialia; (United States) Vol. 41:10; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALLOY SYSTEMS
ALLOYS
AUSTENITE
CARBIDES
CARBON ADDITIONS
CARBON COMPOUNDS
CHEMICAL COMPOSITION
DIAGRAMS
EQUILIBRIUM
IRON ALLOYS
MATHEMATICAL MODELS
NIOBIUM CARBIDES
NIOBIUM COMPOUNDS
NIOBIUM NITRIDES
NITRIDES
NITROGEN COMPOUNDS
PHASE DIAGRAMS
PNICTIDES
PRECIPITATION
QUATERNARY ALLOY SYSTEMS
REFRACTORY METAL COMPOUNDS
SEPARATION PROCESSES
SOLUBILITY
THERMODYNAMICS
TITANIUM CARBIDES
TITANIUM COMPOUNDS
TITANIUM NITRIDES
TRANSITION ELEMENT COMPOUNDS
VANADIUM CARBIDES
VANADIUM COMPOUNDS
VANADIUM NITRIDES