Title of article :
Modeling of graphitization kinetics during peritectic melting of tungsten carbide Original Research Article
Author/Authors :
Marios D. Demetriou، نويسنده , , Nasr M. Ghoniem، نويسنده , , Adrienne S. Lavine، نويسنده ,
Issue Information :
دوهفته نامه با شماره پیاپی سال 2002
Pages :
10
From page :
4995
To page :
5004
Abstract :
A dynamic computational model developed within the context of the classical theory of phase evolution is applied to the W-C system to simulate the kinetics of graphite nucleation during non-equilibrium peritectic melting of WC. The kinetic variables used in the model are obtained directly from the free energy formulations that characterize the stable and metastable equilibria between WC, liquid, and graphite. The isothermal kinetic analysis suggests that transformation time decreases monotonically with increasing superheat such that the minimum transformation time occurs at the metastable congruent melting point of WC (~3107 K). To crystallize 1 ppm of graphite, the minimum transformation time is computed to be ~2 ns. The non-isothermal kinetic analysis suggests that under moderate to high heating rates (104-106 K/s) graphitization is completed at superheats of 40-50 K, while under ultra-high heating rates (~108 K/s) graphitization remains incomplete giving rise to metastable congruent melting of WC.
Keywords :
Non-equilibrium processing , Nucleation , Cluster dynamics , Growth , computer simulation
Journal title :
ACTA Materialia
Serial Year :
2002
Journal title :
ACTA Materialia
Record number :
1140106
Link To Document :
بازگشت