Influence of thermomechanical processing on martensitic transformation in 10Cr–18Mn austenitic steel

To improve the shape memory effect (SME) of 304 austenitic steel effectively and efficiently, thermomechanical cycling, comprising deformation at room temperature and annealing, was applied. The influences of cycle number and annealing temperature on the SME and microstructures in 304 austenitic steel were investigated by light microscope (LM), X-ray diffraction (XRD), and transmission electron microscope (TEM). The shape recovery ratio was remarkably improved from 16% to 40% after two thermomechanical cycles. The optimum annealing temperature was 833 K in the process of thermomechanical cycling. The improved SME by thermomechanical cycling was mainly related to stress-induced ε martensite rather than stress-induced α’ martensite. The reason is that thermomechanical cycling can not only promote the occurrence of the stress-induced γ→ε martensitic transformation, but also suppress the subsequently stress-induced ε→α′ transformation.

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In Situ SEM Observation and Analysis of Martensitic Transformation During Short Fatigue Crack Propagation in Metastable Austenitic Steel

Advanced Engineering Materials ◽

10.1002/adem.200900337 ◽

2010 ◽

Vol 12 (4) ◽

pp. 255-261 ◽

Cited By ~ 15

Author(s):

Ulrich Krupp ◽

Ingmar Roth ◽

Hans-Jürgen Christ ◽

Martin Kübbeler ◽

Claus-Peter Fritzen

Keyword(s):

Fatigue Crack ◽

Martensitic Transformation ◽

Crack Propagation ◽

Austenitic Steel ◽

Fatigue Crack Propagation ◽

Sem Observation ◽

Metastable Austenitic Steel ◽

Short Fatigue Crack

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Reversible Martensitic Transformation Produced by Severe Plastic Deformation of Metastable Austenitic Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.738-739.491 ◽

2013 ◽

Vol 738-739 ◽

pp. 491-495 ◽

Cited By ~ 4

Author(s):

Igor Litovchenko ◽

Alexander Tyumentsev ◽

Alexander V. Korznikov

Keyword(s):

Plastic Deformation ◽

High Pressure ◽

Martensitic Transformation ◽

Severe Plastic Deformation ◽

Dynamic Recrystallization ◽

Austenitic Steel ◽

High Pressure Torsion ◽

Martensitic Transformations ◽

Metastable Austenitic Steel ◽

Nanostructured States

The peculiarities of martensitic transformations and formation of nanostructured states in metastable austenitic steel (Fe-18Cr-8Ni-Ti) after severe plastic deformation by high pressure torsion are investigated. It is shown that during severe plastic deformation with increased strain rate not only direct (γ→α΄) but also reverse (α΄→γ) martensitic transformations occur, which is revealed by the changes in the volume content of α΄ - martensite during deformation. The fragments thought to be formed by direct and reverse martensitic transformations and those of dynamic recrystallization of austenite are observed.

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The Role of Martensitic Transformation in Thermomechanical Development of Microstructure and Plasticity of Two-Phase Ti-6Al-4V Titanium Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.687.3 ◽

2016 ◽

Vol 687 ◽

pp. 3-10 ◽

Cited By ~ 1

Author(s):

Maciej Motyka ◽

Jan Sieniawski ◽

Waldemar Ziaja

Keyword(s):

Plastic Deformation ◽

Titanium Alloy ◽

Martensitic Transformation ◽

Titanium Alloys ◽

Thermomechanical Processing ◽

Solution Treatment ◽

Phase Morphology ◽

Two Phase ◽

Α Phase ◽

Hot Plasticity

Phase constituent morphology in microstructure of two-phase α+β titanium alloys is determined by conditions of thermomechanical processing consisting of sequential heat treatment and plastic deformation operations. Results of previous research indicate that particularly solution treatment preceding plastic deformation significantly changes α-phase morphology and determines hot plasticity of titanium alloys. In the paper thermomechanical processing composed of β solution treatment and following hot forging of Ti-6Al-4V titanium alloy was analysed. Development of martensite plates during heating up and hot deformation was evaluated. Microscopic examinations revealed that elongated and deformed α-phase grains were fragmented and transformed into globular ones. Significant influence of martensitic transformation on elongation coefficient of α-phase grains after plastic deformation was confirmed. Based on results of elevated temperature tensile tests it was established that α-phase morphology in examined two-phase α+β titanium alloy, developed in the thermomechanical processing, can enhance their hot plasticity – especially in the range of low strain rates.

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Influence of Thermomechanical Processing on the Martensitic Transformation Temperatures of NiTi SMA Wire

Materials Science Forum ◽

10.4028/www.scientific.net/msf.643.43 ◽

2010 ◽

Vol 643 ◽

pp. 43-48 ◽

Cited By ~ 3

Author(s):

Leonardo Kyo Kabayama ◽

Odair Doná Rigo ◽

Jorge Otubo

Keyword(s):

Martensitic Transformation ◽

Thermomechanical Processing ◽

Cold Drawing ◽

Wire Drawing ◽

Mechanical Processing ◽

Drawing Process ◽

Intermediate Annealing ◽

Transformation Temperatures ◽

Area Reduction ◽

Niti Sma

Most of the applications of NiTi SMA are as a wire form. In this sense it is important to know the effects of thermo-mechanical processing such as reduction per pass and intermediate annealing on the wire drawing process. For this work they were produced wire by cold drawing using 15 % area reduction per pass with and without intermediate annealing. The starting ingot was produced by VIM process. The influence of thermo-mechanical processing will be related to the martensitic transformation temperatures.

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