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Deformation Behaviour and Microstructural Evolution During Hot Compression of AISI 904L
Author(s) -
Bradaskja B.,
Pirnar B.,
Fazarinc M.,
Fajfar P.
Publication year - 2011
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201000036
Subject(s) - materials science , strain rate , deformation (meteorology) , softening , microstructure , dynamic recrystallization , composite material , atmospheric temperature range , metallurgy , grain size , austenite , compression (physics) , deformation bands , dislocation , hot working , thermodynamics , physics
The hot deformation behaviour and microstructural evolution of AISI 904L super‐austenitic steel has been investigated by means of hot compression tests. The tests were carried out on a Gleeble 1500D thermo‐mechanical simulator in the temperature range from 850 °C to 1150 °C and at strain rates range from 0.001 s −1 to 5 s −1 . The microstructure evolution was examined by means of light optical microscopy (LOM). The results show that after an initial deformation hardening, softening mechanisms occur. The peak stress level decreases with increasing deformation temperature and decreasing strain rate, which can be represented by a Zener–Hollomon parameter in the hyperbolic‐sine equation with the activation energy for deformation of 463 kJ/mol. The steady state was achieved at maximum strain of 0.9 only at the lower strain rates (under 1 s −1 ) and the higher temperatures (above 1100 °C). Microstructural analyses showed a gradual increase in the dynamically recrystallized area with an increase of the temperature and a decrease of the strain rate. The grain size did change, as expected, correlating to the deformation conditions.