Bauschinger effects and work-hardening in spheroidized steels

Technical Report · Sun May 01 04:00:00 EDT 1977

DOI:https://doi.org/10.2172/7301123· OSTI ID:7301123

Chang, Y W

The effects of cementite particles and subgrain boundaries on work-hardening behavior of spheroidized carbon steels were investigated by making direct measurements of residual internal stresses. These internal stresses developed due to plastic incompatibilities between elastic particles and an elastic-plastic matrix. A continuum analysis of these internal stress fields, based upon a multiple slip model, is presented and is found to be in good accord with the experiments. The internal stresses appear to saturate in the plastic strain range of 3 approx. 5% where a transition in strain-hardening behavior was observed (''double-n'' behavior), and to contribute approximately 20% to total work-hardening. The cementite-particle-pinned-subgrain-boundaries, formed during a post-quench annealing treatment, were found to lower the internal stress, thus indicating that they assisted the relaxation processes of entrapped Orowan loops by acting as sources of dislocations. The flow stress increment in dispersion hardened alloys due to work-hardening consisted of internal stress, forest stress, and source-shortening stress. The flow stress curves of spheroidized carbon steels were found to be described by a modified mean-square-root addition law of the form: sigma/sub f/ = sigma/sub epsilon/sub p/=0/ = sigma/sup i/ ((..delta..sigma/sup s/)/sup 2/ + (..delta..sigma/sup ss/)/sup 2/ + (sigma/sup f/)/sup 2/)/sup 1///sup 2/.The maximum normal interfacial stresses were estimated from the data. The maximum values occurred in the tensile direction at the poles of particles and the magnitude was found to be approximately one half of flow stress. The significance of these stresses regarding interface cavitation is discussed briefly.

• Research Organization: Brown Univ., Providence, RI (USA). Div. of Engineering
• Sponsoring Organization: US Energy Research and Development Administration (ERDA)
• OSTI ID: 7301123
• Report Number(s): COO-3084-51
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CARBIDES
CARBON COMPOUNDS
CARBON STEELS
CEMENTITE
CRYSTAL STRUCTURE
FLOW STRESS
HARDENING
INTERMETALLIC COMPOUNDS
IRON ALLOYS
IRON BASE ALLOYS
IRON CARBIDES
IRON COMPOUNDS
MATHEMATICAL MODELS
MICROSTRUCTURE
STEELS
STRAIN HARDENING
STRESSES
TRANSITION ELEMENT COMPOUNDS