Self-Accommodated Dual Γ/Ε Phase Deformation Microstructure Accompanying a Reverse Transformation of Deformation-Induced Ε-Martensite

2020 ◽  
Author(s):  
Alok Singh ◽  
Takahiro Sawaguchi
Keyword(s):  
Reverse Transformation ◽  
Deformation Microstructure ◽  
Phase Deformation ◽  
Ε Phase ◽  
Ε Martensite

scholarly journals Effect of the γ→ε Phase Transition on Transformation-Induced Plasticity (TRIP) of Nickel-Free High Nitrogen Steel at Low Temperatures

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 710
Author(s):  
Natalia Narkevich ◽  
Yevgeny Deryugin ◽  
Yury Mironov
Keyword(s):  
Volume Fraction ◽  
Tensile Load ◽  
X Ray Diffraction ◽  
High Nitrogen Steel ◽  
Transformation Induced Plasticity ◽  
X Ray ◽  
Root Cause ◽  
Nitrogen Steel ◽  
Ε Phase ◽  
Ε Martensite

The deformation behavior, mechanical properties, and microstructure of Fe-Cr-Mn-0.53%N austenitic stainless steel were studied at a temperature range of 77 up to 293 K. The dynamics of the steel elongation were non-monotonic with a maximum at 240–273 K, when peaks of both static atom displacements from their equilibrium positions in austenite and residual stresses in the tensile load direction were observed. The results of X-ray diffraction analysis confirmed that the only stress-induced γ→ε-martensite transformation occurred upon deformation (no traces of the γ→α′ one was found). In this case, the volume fraction of ε-martensite was about 2–3%. These transformation-induced plasticity (TRIP) patterns were discussed in terms of changes in the phase composition of steel as the root cause.

Formation, reverse transformation, and properties of ε-martensite phase in the CoCrFeMnNi high-entropy alloy under high-pressure

2019 ◽  
Vol 779 ◽  
pp. 1-6 ◽  
Author(s):  
Pengfei Yu ◽  
Lijun Zhang ◽  
Hu cheng ◽  
Hu Tang ◽  
Jiantao Fan ◽  
...  
Keyword(s):  
High Pressure ◽  
Martensite Phase ◽  
Reverse Transformation ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Ε Martensite

The Effect of Cyclic Transformation on the Shape Memory Characteristic in an Fe-Mn-Si-Cr-Ni alloy

1991 ◽  
Vol 246 ◽  
Author(s):  
Hideyuki Ohtsuka ◽  
S. Kajiwara ◽  
T. Ishihara
Keyword(s):  
Shape Memory ◽  
Nuclear Power ◽  
Optical Microscope ◽  
Reverse Transformation ◽  
Recovery Stress ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Ε Martensite ◽  
Memory Characteristic ◽  
Memory Characteristics

AbstractEvaluation of the shape memory characteristics under thermal and stress cycles is indispensable to ensure the reliability of shape memory alloys used in nuclear power reactors. Then the effect of γ↔E cyclic transformation on the shape memory characteristics was investigated in Fe-14Mn-6Si-9Cr-5Ni (wt%) alloy. ε martensites were stress-induced by pulling specimens at room temperature, and they were reverse transformed by heating under various stresses. The change of surface relief during reverse transformation was observed by a hightemperature optical microscope equipped with a tensile machine. The recovery stress was measured by this apparatus after the “yclic transformation” was repeated various times. The reverse-transformed microstructures were observed by transmission electron microscopy. As a result, the amount of residual ε martensite increased with increasing stress applied during reverse transformation. As the “cyclic transformation” was repeated, the recovery stress remarkably increased at first, and then gradually decreased. This rapid increase of recovery stress is attributed to not only the increase of elongation when specimen is deformed but also the increase of stacking faults which act as nucleation sites of martensite. The decrease of recovery stress is attributed to the decrease of elongation.

Influence of Cold Plastic Deformation on the Development of the Texture in High-Manganese Austenitic Steel

2013 ◽  
Vol 203-204 ◽  
pp. 115-120 ◽  
Author(s):  
Joanna Kowalska ◽  
Wiktoria Ratuszek ◽  
Małgorzata Witkowska ◽  
Anna Zielińska-Lipiec
Keyword(s):  
Mechanical Twinning ◽  
Cold Plastic Deformation ◽  
High Manganese ◽  
X Ray ◽  
Ε Phase ◽  
Ε Martensite ◽  
Cold Rolled ◽  
Casting Steel ◽  
Hot Rolled ◽  
High Manganese Austenitic Steel

The research was carried out on 26Mn-3Si-3Al steel having a low value of SFE. After casting, steel was forged and hot-rolled at the temperatures within the range of from 1200°C to 900. Next, the steel was cold rolled until the deformation of 66% was obtained. Upon the basis of X-ray examination and the observations of microstructures, it was found out that during cold rolling mechanical twinning and the martensitic transformation of austenite in hcp-ε martensite occurred. The crystallographic texture of the γ phase (austenite) and ε phase (martensite) was also examined.

scholarly journals Precipitation during γ-ε Phase Transformation in Biomedical Co-Cr-Mo Alloys Fabricated by Electron Beam Melting

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 71
Author(s):  
Kosuke Ueki ◽  
Motoka Kasamatsu ◽  
Kyosuke Ueda ◽  
Yuichiro Koizumi ◽  
Daixiu Wei ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Electron Beam ◽  
Phase Stability ◽  
Electron Beam Melting ◽  
Stability Region ◽  
Reverse Transformation ◽  
Metallic Elements ◽  
Σ Phase ◽  
The Matrix ◽  
Ε Phase

We studied the precipitates that were induced during γ-ε phase transformation in biomedical Co-28Cr-6Mo (mass%) alloys that were fabricated by electron beam melting with carbon contents of 0.184 and 0.018 mass%. In the high-C as-built alloy, M23X6-type, π-phase (M3T2X-type), and η-phase (M6X-M12X-type) precipitates were observed (M and T: metallic elements, X: C and/or N). σ-phase (Co(Cr,Mo)), π-phase, and Co3Mo2Si-type precipitates were observed in the low-C as-built alloy. This is the first report that shows the presence and chemical composition of this precipitate, as the Co3Mo2Si-type precipitate has not been detected in biomedical Co-Cr-Mo alloys before. After aging in the ε-phase stability region, the high-C and low-C alloys both contained a single ε-phase matrix, and the amount of π-phase precipitates increased. Conversely, the amount of π-phase precipitates in both alloys decreased when a reverse transformation treatment was applied in the γ-phase stability region after aging. In the low-C alloy, the amount of Co3Mo2Si-type precipitates increased after reverse transformation treatment. These results indicate that the dissolution of π-phase precipitates and the formation of Co3Mo2Si-type precipitates during reverse transformation promote the formation of fine γ-phase grains at the precipitate/ε-phase matrix interface, because the formation and dissolution of these precipitates affect the γ-phase stability of the matrix.

scholarly journals Comparison of Reverse Transformation Behaviors of Thermally- and Deformation-Induced ε-Martensite in Fe-28Mn-6Si-5Cr Shape Memory Alloy

2016 ◽  
Vol 57 (10) ◽  
pp. 1707-1713 ◽  
Author(s):  
Wataru Tasaki ◽  
Koichi Tsuchiya ◽  
Takahiro Sawaguchi ◽  
Susumu Takamori
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Reverse Transformation ◽  
Ε Martensite

Preferred orientation of rolling-induced ε martensite in an Fe-Mn-Si alloy

2003 ◽  
Vol 112 ◽  
pp. 365-368 ◽  
Author(s):  
K. K. Jee ◽  
W. Y. Jang ◽  
Y. H. Chung
Keyword(s):  
Preferred Orientation ◽  
Ε Martensite
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