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Serrated yielding in 9Cr-1Mo ferritic steel

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Field Value
 
Title Serrated yielding in 9Cr-1Mo ferritic steel
 
Creator CHOUDHARY, BK
RAO, KBS
MANNAN, SL
KASHYAP, BP
 
Subject cr-1 mo steel
stainless-steel
temperature
alloys
flow
fracture
model
 
Description Tensile tests were performed on specimens in quenched and tempered and thermally aged conditions over a wide temperature range (300-873 K) to assess the occurrence of serrated flow, a manifestation of dynamic strain aging (DSA), in 9Cr-1Mo ferritic steel, with an emphasis on the influence of prior thermal aging oil serrated yielding. The alloy exhibited jerky/serrated pow in the load-elongation curves at intermediate temperatures. Types A, B, and C serrations were observed, depending on the test temperature and applied strain rate. The apparent activation energy of 83 kJ mol(-1) measured for serrated flow suggests that diffusion of an interstitial solute such as carbon is responsible for dynamic strain aging in 9Cr-1Mo steel. Prior thermal aging at 793 K for 5000 h and at 873 K for 1000 and 5000 h resulted in a significant decrease in the height of serrations, i.e. the magnitude of the stress drop, as well as an increase in the critical strain for the onset of serrations. Both of these observations indicate reduced propensity to DSA as a result of increased precipitate sinks as well as a reduced carbon concentration in solid solution owing to an increased density of carbides in the thermally aged conditions. Reduced propensity to DSA resulted in a significant reduction in the strength values at intermediate temperatures.
 
Publisher INST MATERIALS
 
Date 2011-08-03T09:42:32Z
2011-12-26T12:54:08Z
2011-12-27T05:41:35Z
2011-08-03T09:42:32Z
2011-12-26T12:54:08Z
2011-12-27T05:41:35Z
1999
 
Type Article
 
Identifier MATERIALS SCIENCE AND TECHNOLOGY, 15(7), 791-797
0267-0836
http://dspace.library.iitb.ac.in/xmlui/handle/10054/8978
http://hdl.handle.net/10054/8978
 
Language en