Investigation on the nucleation mechanism of deformation-induced martensite in an austenitic stainless steel under severe plastic deformation

2007 ◽  
Vol 22 (3) ◽  
pp. 724-729 ◽  
Author(s):  
C.X. Huang ◽  
G. Yang ◽  
Y.L. Gao ◽  
S.D. Wu ◽  
S.X. Li
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nucleation Mechanism ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
Transformation Mechanism ◽  
X Ray ◽  
Angular Pressing ◽  
Transmission Electron

The nucleation mechanism of deformation-induced martensite was investigated by x-ray diffraction and transmission electron microscope in an ultra-low carbon austenitic stainless steel deformed by equal channel angular pressing at room temperature. It was found that two types of martensite transformation mechanism, stress-assisted and strain-induced, occurred via the sequences of γ (fcc) → ɛ (hcp) → α′ (bcc) and/or γ → α′. In both cases, the crystallographic relationships among γ, ɛ, and α′ followed the Kurdjumov-Sachs orientation relationships: {111}γ //{0001}ɛ //{011}α′ and 〈110〉γ//〈1120〉ɛ//〈111〉α′.

Mechanical and Corrosion Properties of a F138 Austenitic Stainless Steel after Deformation by Equal Channel Angular Pressing

2014 ◽  
Vol 783-786 ◽  
pp. 837-841
Author(s):  
Andrea Madeira Kliauga ◽  
V.L. Sordi ◽  
Maurizio Ferrante ◽  
C.A. Rovere ◽  
S.E. Curi
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Equal Channel Angular Pressing ◽  
Equivalent Strain ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Heat Treated ◽  
Mechanical And Corrosion Properties

A F138 austenitic stainless steel was solution heat treated, deformed by equal-channel angular pressing (ECAP) at 25 and 300°C. The equivalent strain was ~0.7 per pass and the applied equivalent strain varied from 0.7 to 2.8. Microstructure evolution was observed by transmission electron microscopy (TEM) electron back-scattered diffraction (EBSD) and X –ray diffraction. Work hardening behavior was studied by making use of Kocks-Mecking plots and hardness measurements, the influence of deformation on corrosion resistance was evaluated recording anodic polarization curves in 0.9% NaCl solution.

Variation of the Reversed Austenite Amount with the Tempering Temperature in a Fe-13%Cr-4%Ni-Mo Martensitic Stainless Steel

2010 ◽  
Vol 650 ◽  
pp. 193-198 ◽  
Author(s):  
Yuan Yuan Song ◽  
Xiu Yan Li ◽  
Fu Xing Yin ◽  
De Hai Ping ◽  
Li Jian Rong ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Martensitic Stainless Steel ◽  
Low Carbon ◽  
Reversed Austenite ◽  
X Ray Diffraction ◽  
Tempering Temperature ◽  
X Ray ◽  
Transmission Electron

Tempering temperature dependence of the amount of the reversed austenite in the range of 570 oC to 680 oC was investigated by means of X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) in a low carbon Fe-13%Cr-4%Ni-Mo (wt.%) martensitic stainless steel. It was found that the reversed austenite began to form at the tempered temperature slightly above the As temperature. As the tempered temperature increased, the amount of the reversed austenite changed little in the temperature range of 580-595 oC. Then, the amount of the reversed austenite increased sharply with the increased tempered temperature. When the tempered temperature increased to about 620 oC, the amount of the reversed austenite exhibited a peak. Afterward, it decreased quickly at the elevated tempered temperature. The microstructural evolvement of the reversed austenite at different tempering temperature was also observed by TEM.

High-density stacking faults in a supersaturated nitrided layer on austenitic stainless steel

2016 ◽  
Vol 49 (6) ◽  
pp. 1967-1971 ◽  
Author(s):  
Ke Tong ◽  
Fei Ye ◽  
Honglong Che ◽  
Ming Kai Lei ◽  
Shu Miao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nitrided Layer ◽  
Stacking Faults ◽  
High Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

The nitrogen-supersaturated phase produced by low-temperature plasma-assisted nitriding of austenitic stainless steel usually contains a high density of stacking faults. However, the stacking fault density observed in previous studies was considerably lower than that determined by fitting the X-ray diffraction pattern. In this work, it has been confirmed by high-resolution transmission electron microscopy that the strip-shaped regions of about 3–25 nm in width observed at relatively low magnification essentially consist of a series of stacking faults on every second {111} atomic plane. A microstructure model of the clustered stacking faults embedded in a face-centred cubic structure was built for these regions. The simulated X-ray diffraction and transmission electron microscopy results based on this model are consistent with the observations.

Microstructure Evolution of a Metastable CrMnN Austenitic Stainless Steel during Compression Deformation

2010 ◽  
Vol 146-147 ◽  
pp. 26-33 ◽  
Author(s):  
Ming Zhou Xu ◽  
Jian Jun Wang ◽  
Li Jun Wang ◽  
Wen Fang Cui ◽  
Chun Ming Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Austenitic Stainless Steel ◽  
Deformation Twin ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compression Deformation ◽  
Transmission Electron

Microstructural evolution of a metastable 18Cr12Mn0.55N austenitic stainless steel during compression deformation was investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM observation showed the occurrence of deformation-induced phase transformation and atypical deformation twin, the deformation-induced phase cannot be identified as austenite or martensite. XRD test showed that the amount of deformation-induced phase is less than the detectable limit of XRD.

Microstructural Evolution of a F138 Austenitic Stainless Steel after Deformation by ECAP and HPT

2014 ◽  
Vol 775-776 ◽  
pp. 482-486 ◽  
Author(s):  
Andrea Madeira Kliauga ◽  
Vitor Luiz Sordi ◽  
Sergey V. Dobatkin
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
High Pressure Torsion ◽  
Equivalent Strain ◽  
Deformation Bands ◽  
X Ray Diffraction ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Heat Treated ◽  
Electron Back Scattered Diffraction

A F138 austenitic stainless steel was solution heat treated, deformed by equal-channel angular pressing (ECAP) at 25, 100, 200, and 300°C. The equivalent strain was ~0.7 per pass and the applied equivalent strain varied from 0.7 to 4.2. The same material was also deformed by high pressure torsion (HPT) at 300 and 480°C, applying 6GPa pressure and 5 turns; the equivalent strain was ~ 4.5 at r/2 and ~5.2 at the vicinity of the disk edge. Microstructure evolution was observed by transmission electron microscopy (TEM) electron back-scattered diffraction (EBSD) and X ray diffraction. The effect of severe plastic deformation was studied at 25 and 300°C: at 25°C further deformation led to the formation of grain subdivision inside deformation bands and the onset of new grains formation after 2 ECAE passes. The deformation at 300 and 400°C up to 6 passes lead to the formation of recrystallized grains of the order of 100 nm size.

Microstructures of two-phase Ti–Cr alloys containing the TiCr2 Laves phase intermetallic

1997 ◽  
Vol 12 (6) ◽  
pp. 1472-1480 ◽  
Author(s):  
Katherine C. Chen ◽  
Samuel M. Allen ◽  
James D. Livingston
Keyword(s):  
Laves Phase ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
Phase Growth ◽  
Two Phase ◽  
X Ray ◽  
Lattice Constants ◽  
Annealing Temperatures ◽  
Transmission Electron ◽  
Phase Intermetallic

Microstructures of two-phase Ti–Cr alloys (Ti-rich bcc + TiCr2 and Cr-rich bcc + TiCr2) are analyzed. A variety of TiCr2 precipitate morphologies is encountered with different nominal alloy compositions and annealing temperatures. Lattice constants and crystal structures are determined by x-ray diffraction (XRD) and transmission electron microscopy (TEM). Orientation relationships between the beta bcc solid solution and C15 TiCr2 Laves phase are understood in terms of geometrical packing, and are consistent with a Laves phase growth mechanism involving twinning.

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