On the ledge mechanism of pearlite growth: The Cu-Al lamellar eutectoid
- Univ. of Surrey, Guildford, Surrey (United Kingdom)
Recently the classical views of pearlite growth were challenged by a series of studies of the three heterophase boundaries present in growing lamellar eutectoids. The ferrite/cementite boundary was found to contain linear defects (direction steps), which maintained a micro-habit plane between the pearlitic phases, in both Fe-C and Fe-C-Mn steels. Observations of the ferrite/austenite and cementite/austenite growth interfaces revealed the presence of facets and growth ledges. From these observations Hackney and Shiflet proposed that pearlite grows from the parent austenite by a co-operative ledge mechanism. The motion of ledges on the growth interface determines the position of the triple points and hence the introduction of direction steps into the inter-lamellar boundary. Further observations have indirectly supported this ledge mechanism of pearlite growth. Direction steps have also been observed at the inter-lamellar boundaries in Cu-Be and Fe-Ti pearlites. This work aims to show that features of the lamellar eutectoid ([beta] [r arrow] [alpha] + [gamma]) in a Cu-11.95 wt%Al alloy can be readily rationalized in terms of a co-operative ledge mechanism.
- OSTI ID:
- 6311757
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Vol. 29:3; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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