Effect of Multistage High Temperature Thermomechanical Treatment on the Microstructure and Mechanical Properties of Austenitic Reactor Steel

The deformation microstructures formed by novel multistage high-temperature thermomechanical treatment (HTMT) and their effect on the mechanical properties of austenitic reactor steel are investigated. It is shown that HTMT with plastic deformation at the temperature decreasing in each stage (1100, 900, and 600 °C with a total strain degree of e = 2) is an effective method for refining the grain structure and increasing the strength of the reactor steel. The structural features of grains, grain boundaries and defective substructure of the steel are studied in two sections (in planes perpendicular to the transverse direction and perpendicular to the normal direction) by Scanning Electron Microscopy with Electron Back-Scatter Diffraction (SEM EBSD) and Transmission Electron Microscopy (TEM). After the multistage HTMT, a fragmented structure is formed with grains elongated along the rolling direction and flattened in the rolling plane. The average grain size decreases from 19.3 µm (for the state after solution treatment) to 1.8 µm. A high density of low-angle boundaries (up to ≈ 80%) is found inside deformed grains. An additional cold deformation (e = 0.3) after the multistage HTMT promotes mechanical twinning within fragmented grains and subgrains. The resulting structural states provide high strength properties of steel: the yield strength increases up to 910 MPa (at 20 °C) and up to 580 MPa (at 650 °C), which is 4.6 and 6.1 times higher than that in the state after solution treatment (ST), respectively. The formation of deformed substructure and the influence of dynamic strain aging at an elevated tensile temperature on the mechanical properties of the steel are discussed. Based on the results obtained, the multistage HTMT used in this study can be applied for increasing the strength of austenitic steels.

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The Microstructure and Mechanical Properties of Ferritic-Martensitic Steel EP-823 after High-Temperature Thermomechanical Treatment

Metals ◽

10.3390/met12010079 ◽

2022 ◽

Vol 12 (1) ◽

pp. 79

Author(s):

Igor Litovchenko ◽

Kseniya Almaeva ◽

Nadezhda Polekhina ◽

Sergey Akkuzin ◽

Valeria Linnik ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Plastic Deformation ◽

High Temperature ◽

Thermomechanical Treatment ◽

Martensitic Steel ◽

Rolling Plane ◽

Dynamic Strain ◽

Temperature Range ◽

Microstructure And Mechanical Properties

The effect of high-temperature thermomechanical treatment (HTMT) with plastic deformation by rolling in austenitic region on the microstructure and mechanical properties of 12% chromium ferritic-martensitic steel EP-823 is investigated. The features of the grain and defect microstructure of steel are studied by Scanning Electron Microscopy with Electron Back-Scatter Diffraction (SEM EBSD) and Transmission Electron Microscopy (TEM). It is shown that HTMT leads to the formation of pancake structure with grains extended in the rolling direction and flattened in the rolling plane. The average sizes of martensitic packets and ferrite grains are approximately 1.5–2 times smaller compared to the corresponding values after traditional heat treatment (THT, which consists of normalization and tempering). The maximum grain size in the section parallel to the rolling plane increases up to more than 80 µm. HTMT leads to the formation of new sub-boundaries and a higher dislocation density. The fraction of low-angle misorientation boundaries reaches up to ≈68%, which exceeds the corresponding value after HTMT (55%). HTMT does not practically affect the carbide subsystem of steel. The mechanical properties are investigated by tensile tests in the temperature range 20–700 °C. It is shown that the values of the yield strength in this temperature range after HTMT increase relative to the corresponding values after THT. As a result of HTMT, the elongation decreases. A significant decrease is observed in the area of dynamic strain aging (DSA). The mechanisms of plastic deformation and strengthening of ferritic-martensitic steel under the high-temperature thermomechanical treatments are also discussed.

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Tailoring a Low Young Modulus for a Beta Titanium Alloy by Combining Severe Plastic Deformation with Solution Treatment

Materials ◽

10.3390/ma14133467 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3467

Author(s):

Anna Nocivin ◽

Doina Raducanu ◽

Bogdan Vasile ◽

Corneliu Trisca-Rusu ◽

Elisabeta Mirela Cojocaru ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Plastic Deformation ◽

Severe Plastic Deformation ◽

Young’S Modulus ◽

Young's Modulus ◽

Solution Treatment ◽

Young Modulus ◽

Orthopedic Implants ◽

Beta Titanium Alloy

The present paper analyzed the microstructural characteristics and the mechanical properties of a Ti–Nb–Zr–Fe–O alloy of β-Ti type obtained by combining severe plastic deformation (SPD), for which the total reduction was of etot = 90%, with two variants of super-transus solution treatment (ST). The objective was to obtain a low Young’s modulus with sufficient high strength in purpose to use the alloy as a biomaterial for orthopedic implants. The microstructure analysis was conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) investigations. The analyzed mechanical properties reveal promising values for yield strength (YS) and ultimate tensile strength (UTS) of about 770 and 1100 MPa, respectively, with a low value of Young’s modulus of about 48–49 GPa. The conclusion is that satisfactory mechanical properties for this type of alloy can be obtained if considering a proper combination of SPD + ST parameters and a suitable content of β-stabilizing alloying elements, especially the Zr/Nb ratio.

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Effect of Coupled Conditions of Thermal Cycle and Dump Environment on Conductivity of 5mol% Yttria Stabilized Zirconia

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.591.245 ◽

2013 ◽

Vol 591 ◽

pp. 245-248 ◽

Cited By ~ 1

Author(s):

Jin Feng Xia ◽

Hong Qiang Nian ◽

Tao Feng ◽

Hai Fang Xu ◽

Dan Yu Jiang

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Transmission Electron Microscopy ◽

High Temperature ◽

Thermal Cycle ◽

Oxygen Sensor ◽

Yttria Stabilized Zirconia ◽

Cyclic Change ◽

Stabilized Zirconia ◽

Transmission Electron

In some applications such as automotive oxygen sensor, 5mol% Y2O3stabilized zirconia (5YSZ) is generally used because it has both excellent ionic conductivity and mechanical properties. The automotive oxygen sensor would experience a cyclic change from high temperature (engine running) environment to the low temperature damp environment (in the tail pipe when vehicle stops). The conductivity change with coupled conditions of thermal cycle and dump environment in the 5mol%Y2O3ZrO2(5YSZ) system was examined by XRD,Impedance spectroscopy and transmission electron microscopy (SEM) in this paper.

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Formation of microstructure and properties of Cu-3Ti alloy in thermal and thermomechanical processes

Archives of Metallurgy and Materials ◽

10.1515/amm-2017-0033 ◽

2017 ◽

Vol 62 (1) ◽

pp. 223-230 ◽

Cited By ~ 1

Author(s):

A. Szkliniarz

Keyword(s):

Mechanical Properties ◽

Electrical Conductivity ◽

Plastic Deformation ◽

Cold Working ◽

Cold Deformation ◽

Solution Treatment ◽

Cold Plastic Deformation ◽

Working Solution ◽

Thermomechanical Processes ◽

Selection Of

Abstract This paper presents the possibilities of forming the microstructure as well as mechanical properties and electrical conductivity of Cu-3Ti alloy (wt.%) in thermal and thermomechanical processes that are a combination of homogenising treatment, hot and cold working, solution treatment and ageing. Phase composition of the alloy following various stages of processing it into the specified semi-finished product was being determined too. It was demonstrated that the application of cold plastic deformation between solution treatment and ageing could significantly enhance the effect of hardening of the Cu-3Ti alloy without deteriorating its electrical conductivity. It was found that for the investigated alloy the selection of appropriate conditions for homogenising treatment, hot and cold deformation as well as solution treatment and ageing enables to obtain the properties comparable to those of beryllium bronzes.

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Texture Evolution and Control of 2524 Aluminum Alloy and Its Effect on Fatigue Crack Propagation Behavior

Applied Sciences ◽

10.3390/app11125550 ◽

2021 ◽

Vol 11 (12) ◽

pp. 5550

Author(s):

Yuqiang Chen ◽

Chuang Xiong ◽

Wenhui Liu ◽

Suping Pan ◽

Yufeng Song ◽

...

Keyword(s):

Electron Microscopy ◽

Aluminum Alloy ◽

Fatigue Crack ◽

Cold Rolling ◽

Texture Evolution ◽

Cold Deformation ◽

Solution Treatment ◽

Second Phase ◽

Fatigue Crack Growth Resistance ◽

Volume Fractions

The influences of cold rolling and subsequent heat treatment on the microstructure evolution of 2524 alloy were investigated using an orientation distribution function (ODF) and electron back-scattered diffraction (EBSD). A preparation method of 2524-T3 aluminum alloy with a strong Brass texture was developed, and its effect on the fatigue properties of the alloy was investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that with the increase in cold rolling deformation from 0% to 80%, the volume fractions of Brass, copper, and S textures in the 2524-T3 alloy also increase, especially in the case of Brass and S textures. However, the volume fractions of cube and Goss textures are reduced significantly, especially for cube textures, which are decreased by 57.4%. Reducing coarse second-phase particles (CSPs) is conducive to the formation of a strong deformation texture during cold rolling. A 10% deformation at each rolling pass, followed by a step annealing, helps the preservation of a Brass texture even after solution treatment at 500 °C for 0.5 h, while a large cold deformation followed by high-temperature annealing helps the formation of a strong cube texture. The Brass texture can enhance the strength while decreasing the fatigue crack growth resistance of this alloy.

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Relation Between Structure and Mechanical Properties of High-strength Low-alloy Martensitic Steels after High Temperature Thermomechanical Treatment

Strength of Metals and Alloys ◽

10.1016/b978-1-4832-8412-5.50227-7 ◽

1979 ◽

pp. 1377-1382 ◽

Cited By ~ 2

Author(s):

G. Zouhar ◽

P. Finke ◽

A. Güth ◽

M. Schaper ◽

H.-J. Klauss

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Thermomechanical Treatment ◽

High Strength ◽

Martensitic Steels

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Effect of Solution Temperature on the Microstructure and Mechanical Properties of Wrought 316LN Stainless Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.915-916.576 ◽

2014 ◽

Vol 915-916 ◽

pp. 576-582 ◽

Cited By ~ 1

Author(s):

H. C. Wu ◽

B. Yang ◽

Ming Xian Zhang ◽

Sheng Long Wang ◽

Y. Z. Shi

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Stainless Steel ◽

Solution Treatment ◽

Solution Temperature ◽

Tensile Fracture ◽

316Ln Stainless Steel ◽

Microstructure And Mechanical Properties ◽

Average Grain Size ◽

Fracture Morphologies

The effect of forging and solution temperature on the microstructure and mechanical properties of 316LN stainless steel has been investigated by optical microscope, tensile testing machine and scanning electron microscope (SEM). The results show that the average grain size of the steel was refined from 150μm to 70μm after forging and solution treatment. With increasing solution temperature, the tensile strength and yield strength decreased. On the contrary, the elongation of the steel increased with increasing solution temperature except at 1200°C. The tensile strength of the samples forged at 1100°C is better than those of the samples forged at 1000 and 1200°Cafter solution treatment. Tensile fracture morphologies observation showed that all the specimens have ductile fracture morphologies. With increasing solution temperature, the toughness of the steel becomes better and better except at 1200°C. Both the microstructure and mechanical properties of the 316LN stainless steel have been improved after forging at 1100°C and following by solution treatment at 1150°C.

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Effect of Different Cooling Regimes on the Mechanical Properties of Cementitious Composites Subjected to High Temperatures

The Scientific World JOURNAL ◽

10.1155/2014/289213 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Jiangtao Yu ◽

Wenfang Weng ◽

Kequan Yu

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Scanning Electron Microscopy ◽

High Temperature ◽

Significant Influence ◽

Microstructural Characterization ◽

Cementitious Composite ◽

Engineered Cementitious Composite ◽

Before And After ◽

Scanning Electron

The influence of different cooling regimes (quenching in water and cooling in air) on the residual mechanical properties of engineered cementitious composite (ECC) subjected to high temperature up to 800°C was discussed in this paper. The ECC specimens are exposed to 100, 200, 400, 600, and 800°C with the unheated specimens for reference. Different cooling regimens had a significant influence on the mechanical properties of postfire ECC specimens. The microstructural characterization was examined before and after exposure to fire deterioration by using scanning electron microscopy (SEM). Results from the microtest well explained the mechanical properties variation of postfire specimens.

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