The Influence of Plastic Deformation on Lattice Defect Structure and Mechanical Properties of 316L Austenitic Stainless Steel

2017 ◽  
Vol 885 ◽  
pp. 13-18 ◽  
Author(s):  
Moustafa El-Tahawy ◽  
Jenő Gubicza ◽  
Yi Huang ◽  
Hye Lim Choi ◽  
Hee Man Choe ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Dislocation Density ◽  
Defect Structure ◽  
High Pressure Torsion ◽  
Defect Density ◽  
Lattice Defect ◽  
Coarse Grained ◽  
316L Austenitic Stainless Steel ◽  
Processed Sample

The effect of different plastic deformation methods on the phase composition, lattice defect structure and hardness in 316L stainless steel was studied. The initial coarse-grained γ-austenite was deformed by cold rolling (CR) or high-pressure torsion (HPT). It was found that the two methods yielded very different phase compositions and microstructures. Martensitic phase transformation was not observed during CR with a thickness reduction of 20%. In γ-austenite phase in addition to the high dislocation density (~10 × 1014 m-2) a significant amount of twin-faults was detected due to the low stacking fault energy. On the other hand, γ-austenite was gradually transformed into ε and α’-martensites with transformation sequences γ→ε→α’ during HPT deformation. A large dislocation density (~133 × 1014 m-2) was detected in the main phase (α’-martensite) at the periphery of the disk after 10 turns of HPT. The high defect density is accompanied by a very small grain size of ~45 nm in the HPT-processed sample, resulting in an very large hardness of 6130 MPa.

Magnetic Characterization of SUS316L Deformed by High Pressure Torsion

2011 ◽  
Vol 239-242 ◽  
pp. 1300-1303
Author(s):  
Hong Cai Wang ◽  
Minoru Umemoto ◽  
Innocent Shuro ◽  
Yoshikazu Todaka ◽  
Ho Hung Kuo
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Stainless Steel ◽  
Phase Transformation ◽  
Austenitic Stainless Steel ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Austenitic Matrix ◽  
Magnetic Characterization

SUS316L austenitic stainless steel was subjected to severe plastic deformation (SPD) by the method of high pressure torsion (HPT). From a fully austenitic matrix (γ), HPT resulted in phase transformation from g®a¢. The largest volume fraction of 70% a¢ was obtained at 0.2 revolutions per minute (rpm) while was limited to 3% at 5rpm. Pre-straining of g by HPT at 5rpm decreases the volume fraction of a¢ obtained by HPT at 0.2rpm. By HPT at 5rpm, a¢®g reverse transformation was observed for a¢ produced by HPT at 0.2rpm.

Investigation of Lattice Defects in a Plastically Deformed High-Entropy Alloy

2017 ◽  
Vol 885 ◽  
pp. 74-79 ◽  
Author(s):  
Anita Heczel ◽  
Yi Huang ◽  
Terence G. Langdon ◽  
Jenő Gubicza
Keyword(s):  
High Pressure Torsion ◽  
Lattice Defect ◽  
High Entropy Alloy ◽  
Disk Radius ◽  
High Entropy ◽  
Transmission Electron ◽  
Profile Line ◽  
Size Evolution ◽  
Processed Sample ◽  
Very High

The lattice defect structure developed during plastic deformation in a High-Entropy Alloy (HEA) with the composition of Ti35Zr27.5Hf27.5Nb5Ta5 was investigated. The crystallite size as well as the density and types of dislocations in a disk processed by High-Pressure Torsion (HPT) were determined by X-ray profile line analysis (XLPA). Additional transmission electron microscopy (TEM) investigations were carried out to monitor the grain size evolution during deformation. It was found that the dislocation density in the HPT-processed sample was very high compared to conventional materials. In addition, in Ti35Zr27.5Hf27.5Nb5Ta5 HEA the initial body-centered cubic structure transformed into a martensitic phase during HPT. The hardness of this HEA was investigated along the HPT-processed disk radius and correlated to the microstructure.

Phase Transformations in Pearlitic Steels Induced by Severe Plastic Deformation

2006 ◽  
Vol 114 ◽  
pp. 133-144 ◽  
Author(s):  
Julia Ivanisenko ◽  
Ian MacLaren ◽  
Xavier Sauvage ◽  
Ruslan Valiev ◽  
Hans Jorg Fecht
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Phase Transformations ◽  
High Pressure Torsion ◽  
Pearlitic Steel ◽  
Carbon Steels ◽  
Coarse Grained ◽  
Cold Plastic Deformation ◽  
The Stability ◽  
Nanocrystalline Ferrite

The paper presents an overview of a number of unusual phase transformations which take place in pearlitic steels in conditions of the severe deformation, i.e. combination of high pressure and strong shear strain. Strain-induced cementite dissolution is a well-documented phenomenon, which occurs during cold plastic deformation of pearlitic steels. Recently new results which can shed additional light on the mechanisms of this process were obtained thanks to 3DAP and HRTEM investigations of pearlitic steel deformed by high pressure torsion (HPT). It was shown that the process of cementite decomposition starts by carbon depletion from the carbides, which indicates that the deviation of cementite’s chemical composition from the stoichiometric is the main reason for thermodynamic destabilisation of cementite during plastic deformation. Important results were obtained regarding the distribution of released carbon atoms in ferrite. It was experimentally confirmed that carbon segregates to the dislocations and grain boundaries of nanocrystalline ferrite. Another unusual phase transformation taking place in nanocrystalline pearlitic steel during room temperature HPT is a stress induced α→γ transformation, which never occurs during conventional deformation of coarse grained iron and carbon steels. It was concluded that this occurred due to a reverse martensitic transformation. The atomistic mechanism and the thermodynamics of the transformation, as well as issues related to the stability of the reverted austenite will be discussed.

Submicrocrystalline Austenitic Stainless Steel Processed by Cold or Warm High Pressure Torsion

2016 ◽  
Vol 838-839 ◽  
pp. 398-403 ◽  
Author(s):  
Marina Tikhonova ◽  
Nariman Enikeev ◽  
Ruslan Z. Valiev ◽  
Andrey Belyakov ◽  
Rustam Kaibyshev
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Severe Plastic Deformation ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Submicrocrystalline Structure ◽  
Ultrafine Grained ◽  
Different Temperatures

The formation of submicrocrystalline structure during severe plastic deformation and its effect on mechanical properties of an S304H austenitic stainless steel with chemical composition of Fe – 0.1C – 0.12N – 0.1Si – 0.95Mn – 18.4Cr – 7.85Ni – 3.2Cu – 0.5Nb – 0.01P – 0.006S (all in mass%) were studied. The severe plastic deformation was carried out by high pressure torsion (HPT) at two different temperatures, i.e., room temperature or 400°C. HPT at room temperature or 400°C led to the formation of a fully austenitic submicrocrystalline structure. The grain size and strength of the steels with ultrafine-grained structures produced by cold or warm HPT were almost the same. The ultimate tensile strengths were 1950 MPa and 1828 MPa after HPT at room temperature and 400°C, respectively.

Microstructure and Thermal Stability of Copper - Carbon Nanotube Composites Consolidated by High Pressure Torsion

2012 ◽  
Vol 729 ◽  
pp. 228-233 ◽  
Author(s):  
P. Jenei ◽  
E.Y. Yoon ◽  
Jenő Gubicza ◽  
Hyoung Seop Kim ◽  
J.L. Lábár ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
High Pressure ◽  
Dislocation Density ◽  
High Pressure Torsion ◽  
Lattice Defect ◽  
Taylor Formula ◽  
Processing Temperature ◽  
Pure Cu ◽  
Thermal Stability Of

Blends of Cu powders and 3 vol. % carbon nanotubes (CNTs), and an additional sample from pure Cu powder were consolidated by High Pressure Torsion (HPT) at room temperature (RT) and 373 K. The grain size, the lattice defect densities as well as the hardness of the pure and composite materials were determined. Due to the pinning effect of CNTs, the dislocation density is about three times larger, while the grain size is about half of that obtained in the sample consolidated from the pure Cu powder. The increase of the HPT-processing temperature from RT to 373 K resulted in only a slight increase of the grain size in the Cu-CNT composite while the dislocation density and the twin boundary frequency were reduced significantly. The flow stress obtained experimentally agrees well with the value calculated by the Taylor-formula indicating that the strength in both pure Cu and Cu-CNT composites is determined mainly by the interaction between dislocations. The addition of CNTs to Cu yields a significantly better thermal stability of the UFG matrix processed by HPT.

Influence of Plastic Deformation on Dissolution Corrosion of Type 316L Austenitic Stainless Steel in Static, Oxygen-Poor Liquid Lead-Bismuth Eutectic at 500°C

CORROSION ◽  
10.5006/2400 ◽  
2017 ◽  
Vol 73 (9) ◽  
pp. 1078-1090 ◽  
Author(s):  
Oksana Klok ◽  
Konstantina Lambrinou ◽  
Serguei Gavrilov ◽  
Erich Stergar ◽  
Tom Van der Donck ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Liquid Lead ◽  
Type 316L ◽  
316L Austenitic Stainless Steel ◽  
Lead Bismuth Eutectic ◽  
Dissolution Corrosion

Evolution of Microstructure and Microhardness in Ti-15Mo β-Ti Alloy Prepared by High Pressure Torsion

2016 ◽  
Vol 879 ◽  
pp. 2555-2560 ◽  
Author(s):  
Kristína Václavová ◽  
Josef Stráský ◽  
Jozef Veselý ◽  
Svetlana Gatina ◽  
Veronika Polyakova ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Dislocation Density ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
Positron Annihilation Spectroscopy ◽  
Equivalent Strain ◽  
Ti Alloys ◽  
Evolution Of Microstructure ◽  
Metastable Beta

The main aim of this study is to analyze the effect of the severe plastic deformation (SPD) on the mechanical properties and defect structure of metastable beta Ti alloys. Experiments were performed on two different β-Ti alloys: Ti-15Mo and Ti-6.8Mo-4.5Fe-1.5Al which were subjected to severe plastic deformation (SPD) by high pressure torsion (HPT). The increase of hardness with increasing equivalent strain was determined by microhardness mapping. Dislocation density was studied by advanced techniques of positron annihilation spectroscopy (PAS). Microhardness and dislocation density increases with increasing equivalent strain inserted by severe plastic deformation.

Effect of Indentation Load on Vickers Hardness of Austenitic Stainless Steel After Hydrogen Charging

2014 ◽  
Author(s):  
Osamu Takakuwa ◽  
Yuta Mano ◽  
Hitoshi Soyama
Keyword(s):  
Plastic Deformation ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Vickers Hardness ◽  
Hydrogen Absorption ◽  
Hardness Test ◽  
Indentation Load ◽  
Hydrogen Charging ◽  
Plastic Deformation Behavior ◽  
316L Austenitic Stainless Steel

In order to reveal the effect of indentation load on Vickers hardness of austenitic stainless steel after hydrogen charging, the Vickers hardness measurements have been conducted with three different indentation load of 0.49, 1.96 and 9.80 N on the surface of type 316L austenitic stainless steel after hydrogen charging. Relationship between plastic deformation behavior during indentation process and hydrogen absorption behavior was revealed. In the Vickers hardness test, Vickers hardness keeps same value though the indentation load varies. Needless to say, the value did not depend on magnitude of the indentation load before hydrogen charging in the present study. However, the Vickers hardness increased along with hydrogen charging time and, interestingly, the increase in the Vickers hardness due to the presence of hydrogen depends on magnitude of the indentation load. In the load of 0.49 N and 9.80 N, the Vickers hardness has a maximum value of 3.04 and 2.04 GPa which is 1.58 and 1.15 times larger than value of 1.73 and 1.70 GPa before hydrogen charging, respectively. The hydrogen-induced hardening behavior observed by the Vickers hardness tests employing different indentation load would be evaluated by the relationship between the plastic deformation depth and the hydrogen absorption depth.

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