Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7983765 | Materials Science and Engineering: A | 2013 | 8 Pages |
Abstract
Flow stress data from isothermal hot compression tests on modified 9Cr-1Mo steel over a wide range of strain rate (0.001-100 sâ1) and temperature (1173-1373 K) were found to follow the universal Dorn power-law equation. Distinct stress regimes were observed with stress exponent values of â¼5 and â¼10 for low and high stress regimes, respectively. The flow behavior is rationalized by invoking resisting stress ÏR for dislocation motion and the modified stress exponent n0 was close to 5 for the entire stress regime. At low stresses, ÏR/G=K(Ï/G) and approaches a constant threshold stress (ÏR/G=ÏH/G) in the high stress regime. This has been attributed to the transition in the mechanism from dislocation climb by-pass over particles at low stresses to Orowan bowing at high stresses. The stress dependence is found to obey rate equation of the form (εÌkT/DLGb)=A0[(ÏâÏR)/G]n0 and the constitutive parameters A0, n0, K and ÏH/G evaluated at different strains were employed for predicting flow stress. The successful prediction of flow stress is reflected by a higher correlation coefficient (R=0.99) and a lower average absolute relative error (6.62%) for the entire investigated hot working domain.
Related Topics
Physical Sciences and Engineering
Materials Science
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Authors
Dipti Samantaray, C. Phaniraj, A.K. Bhaduri, Sumantra Mandal, S.K. Albert,