Nucleation and phase selection in undercooled Fe-Cr-Ni melts: Part I. Theoretical analysis of nucleation behavior

The selection of the primary solidifying phase in undercooled stainless steel melts is theoretically analyzed in terms of nucleation theory. Nucleation phenomena are considered using different models for the solid-liquid interface energy. The classical nucleation theory for sharp interfaces and an improved modification, the diffuse interface theory, are applied. The influence of deviations of the nucleus composition from the overall alloy composition is also revealed. A preferred nucleation of the metastable bcc phase in fcc equilibrium solidification-type alloys is predicted. The critical undercooling of metastable crystallization as a function of alloy composition is calculated for an isoplethal section at 69 at. pct Fe of Fe69Cr31-xNix alloys. The results are summarized in a phase selection diagram predicting the primary solidification mode as a function of undercooling and melt composition.

[1]  Samuel M. Allen,et al.  Microstructural development during solidification of stainless steel alloys , 1989 .

[2]  R. N. Wright,et al.  The microstructure and phase relationships in rapidly solidified type 304 stainless steel powders , 1988 .

[3]  D. Kashchiev.  Solution of the non-steady state problem in nucleation kinetics , 1969 .

[4]  J. M. Vitek,et al.  Microstructural modification of austenitic stainless steels by rapid solidification , 1983 .

[5]  Y. Chang,et al.  A thermodynamic analysis and calculation of the Fe-Ni-Cr phase diagram , 1987, Metallurgical and Materials Transactions A.

[6]  L. Gránásy,et al.  Diffuse interface model of bulk heterogeneous nucleation. , 1994 .

[7]  J. B. Sande,et al.  Rapid solidification of a droplet-processed stainless steel , 1984 .

[8]  László Gránásy,et al.  Diffuse interface theory of nucleation , 1993 .

[9]  David Turnbull,et al.  Rate of Nucleation in Condensed Systems , 1949 .

[10]  D. Herlach,et al.  Theoretical treatment of the solidification of undercooled Fe-Cr-Ni melts , 1992 .

[11]  R. Meyer,et al.  The surface tension in a structural model for the solid-liquid interface , 1976 .

[12]  F. Spaepen.  A structural model for the solid-liquid interface in monatomic systems , 1975 .

[13]  S. David,et al.  Analysis of solidification microstructures in Fe-Ni-Cr single-crystal welds , 1990 .

[14]  C. Thompson,et al.  Homogeneous crystal nucleation in binary metallic melts , 1983 .

[15]  Donald T. Hawkins,et al.  Selected Values of the Thermodynamic Properties of the Elements , 1973 .

[16]  A. Johansen,et al.  Microstructure of Rapidly Solidified Stainless-Steel , 1988 .

[17]  J. Perepezko,et al.  Thermodynamic properties of undercooled liquid metals , 1984 .

[18]  G. Lesoult,et al.  Influence des conditions de solidification sur le déroulement de la solidification des aciers inoxydables austénitiques , 1988 .

[19]  L. Gránásy,et al.  Diffuse Interface Approach to Vapour Condensation , 1993 .

[20]  D. Herlach,et al.  Nucleation and metastable phase formation in undercooled FeCrNi melts , 1994 .

[21]  J. Elmer.  The influence of cooling rate on the microstructure of stainless steel alloys , 1988 .

[22]  G. Cleek.  Book reviewPhysics of non-crystalline solids: edited by J. A. Prins. 667 pages, diagrams, illus. 6 × 9 in. New York, John Wiley & Sons, Interscience, 1965. Price, $27.50 , 1966 .

[23]  R. Becker,et al.  Kinetische Behandlung der Keimbildung in übersättigten Dämpfen , 1935 .