Hall-Petch Relationship of a TWIP Steel

2009 ◽  
Vol 423 ◽  
pp. 147-152 ◽  
Author(s):  
F. de las Cuevas ◽  
Mónica Reis ◽  
A. Ferraiuolo ◽  
G. Pratolongo ◽  
L. Pentti Karjalainen ◽  
...  
Keyword(s):  
Twip Steel ◽  
Tensile Tests ◽  
Grain Sizes ◽  
Strain Behaviour ◽  
Wide Range ◽  
Work Hardening Rate ◽  
Twip Steels ◽  
Complete Recrystallization ◽  
Cold Rolled ◽  
Relationship Of

The grain size dependence of the tensile properties of a TWIP steel has been determined for a wide range of grain sizes obtained by grain growth after complete recrystallization of cold rolled material. The near-linear stress-strain behaviour typical of either TWIP steels or other materials that deform by twinning has been observed, the work hardening rate being larger for the smaller grain sizes. The Hall-Petch slope increases as a function of strain, from 350 MPa μm1/2 for the yield stress to 630 MPa μm1/2 for the maximum uniform strain in the tensile tests, ε  0.40. Profuse twinning is observed in deformed specimens by means of FIB-ISE.

High Speed Deformation of Ultrafine Grained TWIP Steel

2007 ◽  
Vol 561-565 ◽  
pp. 107-110 ◽  
Author(s):  
Rintaro Ueji ◽  
Kenji Harada ◽  
Noriyuki Tsuchida ◽  
Kazutoshi Kunishige
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Twip Steel ◽  
Ultrafine Grain ◽  
Grain Sizes ◽  
Ultrafine Grain Size ◽  
Ultrafine Grained ◽  
Wide Range ◽  
Twip Steels ◽  
Large Work

Tensile properties of twinning induced plasticity (TWIP) steels (31%Mn-3%Al-3%Si-Fe) with various mean grain sizes ranging from ultrafine grain size (1.1μm) to conventional one (35.5μm) at a wide range of strain rates from 10-3sec-1 to 103sec-1 were studied. The ultrafine grained TWIP steel exhibits a large work hardening and keeps an adequate elongation at any strain rate. The strength held to the Hall-Petch relationship at each strain rate and the Hall-Petch slopes do not change largely.

Effect of Si Content on Fracture Behaviour Change by Strain Rate in Si Steels

2010 ◽  
Vol 654-656 ◽  
pp. 1303-1306 ◽  
Author(s):  
Takashi Mizuguchi ◽  
Ryota Oouchi ◽  
Rintaro Ueji ◽  
Yasuhiro Tanaka ◽  
Kazunari Shinagawa
Keyword(s):  
Strain Rate ◽  
Fracture Behaviour ◽  
Tensile Tests ◽  
Strain Rates ◽  
Wide Range ◽  
Work Hardening Rate ◽  
Brittle Fractures ◽  
Mechanism Transition ◽  
Si Content ◽  
Si Addition

Fracture behaviour transitions due to change in the strain rate in steels with various Si content ranging from 2% to 5 wt% were studied. Room-temperature tensile tests were conducted over wide range of strain rates ranging from 10-3 s-1 to 103 s-1. Concerning of the steels with low Si content (no more than 3%), the nominal stress - nominal strain curves represented both uniform and local elongations at all strain rates. On the other hand, in 4% Si steel at a strain rate higher than 101 s-1, the tensile sample broke down without local elongation (necking). The stress at breaking was found to be nearly equal to its work hardening rate. The strain rate at which fracture behaviour transition took place in 5% Si steel (10-1s-1) was lower than that in 4% Si steel. TEM observations clarified the existence of deformation twins in the sample that fractured without necking. These results indicated that Si addition is subject to the brittle fractures and that the fracture mechanism transition is closely related with the deformation twinning behaviour.

Recrystallisation Behaviour of an Fe-Mn-C-Si-Al TWIP

2012 ◽  
Vol 715-716 ◽  
pp. 649-654 ◽  
Author(s):  
Lieven Bracke ◽  
Nieves Cabañas-Poy
Keyword(s):  
Grain Size ◽  
Cold Rolling ◽  
Annealing Temperature ◽  
Twip Steel ◽  
Rolling Texture ◽  
Annealing Temperatures ◽  
Twip Steels ◽  
Cold Rolled ◽  
Main Components ◽  
Cold Rolling Texture

The static recrystallisation behaviour of cold rolled and annealed TWinning Induced Plasticity (TWIP) steels is important for its industrial production. The recrystallisation kinetics have been determined for an Fe-Mn-C-Si-Al TWIP steel using hardness measurements and microstructure analysis: it has been shown that recrystallisation progresses rapidly with increased annealing temperature. Recrystallisation was faster at higher cold reductions, and a smaller final grain size was observed at lower annealing temperatures. This indicates that the mechanism is nucleation dominated at lower temperatures; grain growth at higher temperatures appears similar for all reductions. The recrystallisation results in a crystallographic texture where the main components of the cold rolling texture are preserved in the final texture after annealing, although some randomisation was observed.

Effect of Strain Rate on the Microstructures and Properties of Hot–Rolled TWIP Steel in the Solution Condition

2012 ◽  
Vol 430-432 ◽  
pp. 256-259 ◽  
Author(s):  
Yang Yang ◽  
Chun Fu Li ◽  
Kai Hong Song
Keyword(s):  
Strain Rate ◽  
Strain Hardening ◽  
Twip Steel ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Strain Hardening Exponent ◽  
Solution Condition ◽  
Twip Steels ◽  
Hot Rolled ◽  
Strain Hardening Behavior

TWIP steel containing 0.21% C, 24.4% Mn, 0.9% Si, 1.84% Al, 4.61% Cr, 1.89% Ni, 0.41% Mo and 0.012% Nb was investigated. Tensile tests of this steel were performed in the strain rate range of 10−4–10−3 s−1. Results indicate that tensile properties of TWIP steel at room temperature are sensitive to strain rate in the studied range. Analyses on the relationship between strain–hardening exponent and strain rates show that the formation of twins during deformation greatly affects the strain–hardening behavior of TWIP steels.

Evolution of Microstructure and Mechanical Properties during Annealing of Cold Rolled Fe-24Mn-3Al-2Si-1Ni-0.06C Twip Steel

2011 ◽  
Vol 409 ◽  
pp. 719-724 ◽  
Author(s):  
Ahmed A. Saleh ◽  
Azdiar A. Gazder ◽  
Dagoberto Brandao Santos ◽  
Elena V. Pereloma
Keyword(s):  
Twip Steel ◽  
Uniaxial Tensile ◽  
Automotive Applications ◽  
Uniaxial Tensile Testing ◽  
Annealing Twins ◽  
Back Scattering ◽  
Microhardness Testing ◽  
Twip Steels ◽  
Cold Rolled ◽  
Evolution Of Microstructure

TWinning Induced Plasticity (TWIP) steels have been recently developed as a promising material for automotive applications. In the present work the recrystallisation behaviour of 42% cold-rolled Fe-24Mn-3Al-2Si-1Ni-0.06C TWIP steel was investigated during isochronal annealing for 300s via microhardness testing, Electron Back-Scattering Diffraction (EBSD) and uniaxial tensile testing. EBSD internal misorientation data corroborates recrystallised fraction estimates from microhardness measurements. Annealing twins play an important role during recrystallisation by bulging at the deformed grain boundaries during nucleation and generating twin related orientations. During uniaxial tension, the recovered condition recorded three work hardening regions while all partially recrystallised samples exhibited four regions. A modified Hollomon scheme is suggested to account for the effect of strain on microstructure refinement.

Dynamic Strain Aging in the Fe-Mn-Cu-C TWIP Steels

2013 ◽  
Vol 668 ◽  
pp. 861-864 ◽  
Author(s):  
Hai Jun Liu ◽  
Ding Yi Zhu ◽  
Xian Peng ◽  
Zhen Ming Hu ◽  
Ming Jie Wang
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Dynamic Strain Aging ◽  
Strain Aging ◽  
Rate Sensitivity ◽  
Tensile Tests ◽  
Dynamic Strain ◽  
Work Hardening Rate ◽  
Twip Steels ◽  
High Work

Strain rate jump tests were performed on the Fe-Mn-Cu-C TWIP Steels to determine the strain rate sensitivity, and serrated plastic flow was observed in the stress-strain curves during tensile tests at different constant strain rates ranging from 2.5×10-4S-1 to 2.5×10-2S-1. The Fe-Mn-Cu-C TWIP Steels exhibit high work hardening rate and outstanding mechanical properties, The excellent mechanical properties are attributed to dynamic strain aging(DSA) effect, which result from the interaction between Mn(Cu)-C atom atmosphere, C-vacancy, C-C pairs and moving dislocations.

scholarly journals Recrystallization and Mechanical Behavior of High Mn and Low C Cold Rolled and Annealed Steel with TWIP Effect

2012 ◽  
Vol 715-716 ◽  
pp. 579-584 ◽  
Author(s):  
Dagoberto Brandao Santos ◽  
Berenice Mendonça Gonzalez ◽  
Elena V. Pereloma
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Driving Force ◽  
Vickers Microhardness ◽  
Tensile Tests ◽  
Total Elongation ◽  
Strain Hardening Exponent ◽  
Twip Steels ◽  
Cold Rolled ◽  
Annealed Steel

ncreasing demand for automotive vehicles with reduced weight, improved crashworthiness and passengers safety has steamed the research of new Twinning Induced Plasticity (TWIP) steels. In this work the effect of annealing between 400 and 900°C on the microstructure and mechanical properties of hot and cold rolled 0.06C-24Mn-3Al-2Si-1Ni (wt%) steel with TWIP effect was investigated. The results have shown that steel exhibits fast recrystallization kinetics with a low amount of recovery, which results in a high driving force for the former. Mechanical properties were determined using Vickers microhardness and tensile tests. Tensile strength of 670 MPa with 54% of total elongation, and strain hardening exponent of 0.57 were reached after annealing at 900°C.

Submicron/nano Grained Stainless Steel with Superior Mechanical Properties

2005 ◽  
Vol 903 ◽  
Author(s):  
Shreyas Rajasekhara ◽  
M. C. Somani ◽  
M. Koljonen ◽  
L. P. Karjalainen ◽  
A. Kyröläinen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Austenitic Stainless Steels ◽  
Tensile Tests ◽  
Total Elongation ◽  
Fine Grained ◽  
Grain Sizes ◽  
Transmission Electron ◽  
Superior Mechanical Properties ◽  
Cold Rolled

AbstractMetastable austenitic stainless steels may transform to martensite when subjected to cold rolling. Upon subsequent annealing the martensite reverts back to ultra-fine grained austenite. Based on this concept, nano/submicron austenitic grains have been produced in a 63% cold rolled commercial AISI 301LN subjected to annealing treatments at 600°C, 800°C and 1000°C for 1, 10 and 100 seconds.Transmission Electron Microscopy (TEM) observations show the formation of equiaxed austenitic grains as small as ∼ 200nm in samples annealed at 800°C, and a dramatic increase in grain size as the annealing temperature and duration is increased. Additional tensile tests indicate that samples annealed at 800°C for 1 second exhibit a yield strength of ∼ 740 MPa and an total elongation of ∼ 45%. This combination of strength and ductility is excellent exceeding those of conventionally annealed steels (σy=350 MPa; Ductility ∼ 40%) or cold-rolled steels (σy=650 MPa; Ductility ∼ 30%).Finally, a correlation between the observed grain sizes and mechanical properties, in particular the yield strength, is obtained. Preliminary analysis indicates that the Hall-Petch equation can satisfactorily relate the observed yield strength with corresponding grain sizes.

Kinetics of Recrystallization and Grain Growth of Cold Rolled TWIP Steel

2010 ◽  
Vol 89-91 ◽  
pp. 153-158 ◽  
Author(s):  
F. de las Cuevas ◽  
Mónica Reis ◽  
A. Ferraiuolo ◽  
G. Pratolongo ◽  
L. Pentti Karjalainen ◽  
...  
Keyword(s):  
Grain Growth ◽  
Twip Steel ◽  
Growth Equation ◽  
Grain Sizes ◽  
Time Space ◽  
Cold Rolled ◽  
Hot Rolled ◽  
Kinetics Of ◽  
Temperature Time ◽  
Growth Experiments

Hot rolled, laboratory-cast, TWIP steel samples (5.4 mm thick) of 22% Mn - 0.6% C (in mass-%) were cold rolled to different reductions (from 40 % to 70 %) and subsequently isothermally annealed for various times at temperatures ranging from 450º C to 1100º C. The evolution of recrystallization and grain growth was followed by control of the softening kinetics complemented by metallographic, OIM and microtexture observations. A map of the recovery, recrystallization and grain growth in the temperature-time space was obtained. In all instances, the grain size at the end of recrystallization was very fine, D ≤ 2 µm and larger grain sizes were the result of grain growth. A range of grain sizes 2 µm ≤ D ≤ 50 µm was covered by the grain growth experiments. A phenomenological grain growth equation that is useful for the annealing control of this steel was derived from the measurements.

Antineoplastic Activity, Structural Modification, Synthesis and Structure-activity Relationship of Dammarane-type Ginsenosides: An Overview

2019 ◽  
Vol 23 (5) ◽  
pp. 503-516 ◽  
Author(s):  
Qiang Zhang ◽  
Xude Wang ◽  
Liyan Lv ◽  
Guangyue Su ◽  
Yuqing Zhao
Keyword(s):  
Structural Modification ◽  
Gastrointestinal Disease ◽  
Structure Activity Relationship ◽  
Cerebrovascular Diseases ◽  
Activity Relationship ◽  
Cycle Arrest ◽  
Structure Activity ◽  
Wide Range ◽  
Structural Association ◽  
Relationship Of

Dammarane-type ginsenosides are a class of tetracyclic triterpenoids with the same dammarane skeleton. These compounds have a wide range of pharmaceutical applications for neoplasms, diabetes mellitus and other metabolic syndromes, hyperlipidemia, cardiovascular and cerebrovascular diseases, aging, neurodegenerative disease, bone disease, liver disease, kidney disease, gastrointestinal disease and other conditions. In order to develop new antineoplastic drugs, it is necessary to improve the bioactivity, solubility and bioavailability, and illuminate the mechanism of action of these compounds. A large number of ginsenosides and their derivatives have been separated from certain herbs or synthesized, and tested in various experiments, such as anti-proliferation, induction of apoptosis, cell cycle arrest and cancer-involved signaling pathways. In this review, we have summarized the progress in structural modification, shed light on the structure-activity relationship (SAR), and offered insights into biosynthesis-structural association. This review is expected to provide a preliminary guide for the modification and synthesis of ginsenosides.

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