ATOM-PROBE AND STEM STUDIES OF CARBIDE PRECIPITATION IN 2-1/4
CR1MO STEEL
R. C. Thomson and H. K. D. H. Bhadeshia
University of Cambridge
Abstract
Changes in the chemical composition of cementite particles
which initially form by a para-equilibrium transformation
mechanism are studied using atom probe and scanning
transmission electron microscope techniques as a function of
tempering heat treatments. Consistent with our theoretical
predictions, the enrichment of the substitutional solutes in
the carbide at the carbide/matrix interface is not observed to
reach the levels required for local equilibrium at the
interface. Very small clusters of molybdenum and carbon atoms
are found in the ferrite matrix at the early stages of
tempering, although more work is needed to verify this
observation.
APPLIED SURFACE SCIENCE, 1993, Vol.67, No.1-4, pp.334-341
Some of the computer programs associated with this paper can be obtained from the Materials Algorithms Project