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Aspects of Dynamic Recrystallization in Cobalt at High Temperatures

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Title Aspects of Dynamic Recrystallization in Cobalt at High Temperatures
 
Creator KAPOOR, R
PAUL, B
RAVEENDRA, S
SAMAJDAR, I
CHAKRAVARTTY, JK
 
Subject austenitic stainless-steel
hot deformation
alloy 800h
metals
transformation
martensite
nucleation
co
mechanisms
prediction
 
Description Deformation behavior of cobalt in the fcc phase was studied over a wide range of strain rates (0.001 to 1 s(-1)) and temperatures (600 A degrees C to 950 A degrees C). At the lower temperatures and higher strain rates, a single peak in flow stress followed by softening to steady state was observed, whereas at higher temperatures and lower strain rates, an oscillatory flow stress behavior finally converging to a steady state was observed. Both these represent typical flow stress responses during dynamic recrystallization (DRX). The critical condition for the initiation of DRX was determined by the inflection point in the work-hardening vs stress plot. This critical condition in terms of the work done was found to increase with temperature-compensated strain rate. Electron backscattered diffraction (EBSD) revealed that, on quenching after deformation, a certain fraction of the fcc phase was always retained, the extent of retention being higher for smaller grain sizes. Misorientation measurements across boundaries revealed a significant amount of twins in the retained fcc phase. The grain average misorientation (GAM), signifying the misorientation within grains, was found to be inversely related to the twin boundary fractions in the fcc phase.
 
Publisher SPRINGER
 
Date 2011-08-29T09:50:28Z
2011-12-26T12:58:32Z
2011-12-27T05:48:39Z
2011-08-29T09:50:28Z
2011-12-26T12:58:32Z
2011-12-27T05:48:39Z
2009
 
Type Article
 
Identifier METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE, 40A(4), 818-827
1073-5623
http://dx.doi.org/10.1007/s11661-009-9782-8
http://dspace.library.iitb.ac.in/xmlui/handle/10054/12046
http://hdl.handle.net/10054/12046
 
Language en