Microstructure of austenitic stainless steels of various phase stabilities after cyclic and tensile deformation

Tensile and compressive deformation and damage behaviors of Al6XN super-austenitic stainless steels were examined at different strain rates. The deformation and fracture surfaces were characterized by scanning electron microscopy (SEM). It was found that the uniaxial deformation (tensile or compressive) behaviors of Al6XN stainless steel shows a low strain rate sensitivity over the range of 10-4s-1 - 10-2s-1. The tensile and compressive yield strengths measured are nearly comparable. The steel shows a good tensile plasticity. Dislocation slip deformation is the main characteristic of uniaxial deformation. All fracture surfaces induced by tensile deformation at different strain rates can be divided into two parts, i.e., fibrous zone and shear lip zone. The fibrous zone consists of dimples with a bimodal size.

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Analysis of tensile deformation and failure in austenitic stainless steels: Part II – Irradiation dose dependence

Journal of Nuclear Materials ◽

10.1016/j.jnucmat.2009.08.009 ◽

2010 ◽

Vol 396 (1) ◽

pp. 10-19 ◽

Cited By ~ 16

Author(s):

Jin Weon Kim ◽

Thak Sang Byun

Keyword(s):

Stainless Steels ◽

Irradiation Dose ◽

Tensile Deformation ◽

Austenitic Stainless Steels ◽

Dose Dependence ◽

Deformation And Failure

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Tensile Deformation Behaviors of Metastable Austenitic Stainless Steels Studied by Neutron Diffraction

Materials Science Forum ◽

10.4028/www.scientific.net/msf.652.233 ◽

2010 ◽

Vol 652 ◽

pp. 233-237 ◽

Cited By ~ 2

Author(s):

Noriyuki Tsuchida ◽

Kenzo Fukaura ◽

Yo Tomota ◽

Atsushi Moriai ◽

Hiroshi Suzuki

Keyword(s):

Stainless Steels ◽

Volume Fraction ◽

Tensile Deformation ◽

Profile Analysis ◽

Austenitic Stainless Steels ◽

Tensile Tests ◽

Austenite Phase ◽

Lattice Plane ◽

Static Tensile ◽

Deformation Behaviors

Tensile deformation behaviors of three austenitic stainless steels, JIS-SUS310S, 304 and 301L, were studied by static tensile tests and in situ neutron diffraction. In the mechanical properties obtained by the static tensile tests, the 304 and 301L steels showed better balance of tensile strength and uniform elongation than the 310S one because of TRIP effect. The angular dispersion neutron diffractions with a wavelength of 0.16 or 0.182 nm were performed during stepwise tensile testing by using a neutron diffractometer for residual stress analysis (RESA) at the Japan Atomic Energy Agency. The lattice plane strain, stress-induced martensite volume fraction, dislocation density and so on were estimated by the profile analysis as a function of applied stress. The change in lattice plane spacing for austenite indicated four deformation stages. In the comparison of lattice plane strain among the tested steels, a phase stress caused by the stress-induced martensite seems to overlap the intergranular stress of austenite phase. Judging from the results of profile analysis, the strain partitioning of austenite phase in metastable austenitic steels became larger with increasing of the volume fraction of stress-induced martensite during tensile deformation.

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Analyses of Texture and Deformation Mechanism in Fine-Grained Austenitic Stainless Steels by Electron Back Scatter Diffraction

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.218 ◽

2018 ◽

Vol 941 ◽

pp. 218-223

Author(s):

Kyoichi Ishida ◽

Taku Matsuo ◽

Muneyuki Imafuku

Keyword(s):

Phase Transformation ◽

Stainless Steels ◽

Tensile Deformation ◽

Texture Evolution ◽

Austenitic Stainless Steels ◽

Plastic Instability ◽

Electron Back Scatter Diffraction ◽

Fine Grained ◽

Α Phase ◽

Work Hardening Rate

We investigated texture evolution features in fine-grained austenitic stainless steels (JIS-SUS304) under tensile deformation. Three kinds of fine-grained specimens having average grain sizes, d =0.5 μm, 2 μm and 9 μm were prepared. The mechanical properties and phase transformation behaviors of fine grained specimens were compared to those of commercially available SUS304 ( d =16 μm). Tensile test showed increase of yield and tensile strength and decrease of work hardening rate and significant martensitic phase transformation in earlier stage of deformation for 2 μm specimen. These results suggest that simultaneous progress of the dynamic recovery of dislocations in γ-phase and the evolution of harder α’-phase owe the elongation and hardening respectively in fine-grained specimen. From the result of texture analysis, the texture evolution process was different from for each specimen, although the final orientation was almost the same. At the plastic instability stage, an increase of {112}<111>γ phase and a decrease of {112}<113>α’ phase occurred simultaneously for fine-grained 2 μm specimen whereas the opposite tendency was observed for 16 μm specimen. Such a grain size dependence of texture affects an extra ductility of SUS304 at the latter stage of deformation.

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Hydrogen Evolution Behavior during Tensile Deformation in Austenitic Stainless Steels Exposed to High Compressed Hydrogen Atmospheres

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.2519 ◽

2010 ◽

Vol 654-656 ◽

pp. 2519-2522

Author(s):

Keitaro Horikawa ◽

Hidetoshi Kobayashi ◽

Motohiro Kanno

Keyword(s):

Hydrogen Evolution ◽

Stainless Steels ◽

Tensile Deformation ◽

Testing Machine ◽

Austenitic Stainless Steels ◽

Local Deformation ◽

Hydrogen Gas ◽

Deformation And Fracture ◽

Rate Testing ◽

Evolution Behavior

Hydrogen embrittlement sensitivity of austenitic stainless steels, SUS316L and SUS310S exposed to high compressed hydrogen gas atmospheres was evaluated by means of a slow strain rate testing (SSRT) in air. Hydrogen evolution behavior during tensile deformation and fracture was also investigated by using a testing machine equipped with a quadrupole mass spectrometer installed in an ultrahigh vacuum chamber. When the SUS 316L specimen with hydrogen gas charging were deformed at a very slow crosshead speed of 1.67 nm/s, local deformation was promoted as compared to the specimen without hydrogen gas charging. On the other hand, no decrease of the ductility was observed in the SUS310S specimen with hydrogen gas charging even in the SSRT. In the hydrogen charged SUS316L specimen, the amount of continuous hydrogen evolution throughout deformation was much higher than that in the specimen without hydrogen gas charging. In addition, sudden hydrogen evolutions were sometimes identified in the SUS316L specimen with hydrogen gas charging during the deformation.

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