scholarly journals Influence of Hot Consolidation Conditions and Cr-Alloying on Microstructure and Creep in New-Generation ODS Alloy at 1100 °C

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5070 ◽  
Author(s):  
Jiří Svoboda ◽  
Natália Luptáková ◽  
Milan Jarý ◽  
Petr Dymáček
Keyword(s):  
Hot Rolling ◽  
Secondary Recrystallization ◽  
Oxide Dispersion Strengthened ◽  
Coarse Grained ◽  
Mechanically Alloyed ◽  
Creep Properties ◽  
Ods Alloys ◽  
Rolling Temperatures ◽  
New Generation ◽  
Ods Alloy

The coarse-grained new-generation Fe-Al-Y2O3-based oxide dispersion strengthened (ODS) alloys contain 5 vol.% homogeneously dispersed yttria nano-precipitates and exhibit very promising creep and oxidation resistance above 1000 °C. The alloy is prepared by the consolidation of mechanically alloyed powders via hot rolling followed by secondary recrystallization. The paper presents a systematic study of influence of rolling temperature on final microstructure and creep at 1100 °C for two grades (Fe-10Al-4Y2O3 and Fe-9Al-14Cr-4Y2O3 in wt%) of new-generation ODS alloys. The hot rolling temperatures exhibit a rather wide processing window and the influence of Cr-alloying on creep properties is evaluated as only slightly positive.

scholarly journals Fundamental Improvement of Creep Resistance of New-Generation Nano-Oxide Strengthened Alloys via Hot Rotary Swaging Consolidation

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5217
Author(s):  
Jiří Svoboda ◽  
Lenka Kunčická ◽  
Natália Luptáková ◽  
Adam Weiser ◽  
Petr Dymáček
Keyword(s):  
Volume Fraction ◽  
Secondary Recrystallization ◽  
Grain Morphology ◽  
Oxide Dispersion Strengthened ◽  
High Volume ◽  
Coarse Grained ◽  
Mechanically Alloyed ◽  
Rotary Swaging ◽  
New Generation ◽  
Ods Alloy

New-generation oxide dispersion-strengthened (ODS) alloys with a high volume fraction of nano-oxides of 5% are intended to become the leading creep- and oxidation-resistant alloys for applications at 1100–1300 °C. Hot consolidation of mechanically alloyed powders by intensive plastic deformation followed by heat treatment of the alloys are the key aspects for achieving top creep properties, typically ensured by a coarse-grained microstructure strengthened with homogeneously dispersed, very stable yttrium nano-oxides. The rotary swaging method proves to be favourable for hot consolidation of the new-generation ODS alloy presented. Compared to specimens consolidated by hot rolling, consolidation by hot rotary swaging predetermines the formation of coarse grains with a very high aspect ratio during subsequent secondary recrystallization. Such a grain morphology increases the creep strength of the new-generation ODS alloy considerably.

scholarly journals High Temperature Cyclic Plastic Response of New-Generation ODS Alloy

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 804
Author(s):  
Alice Chlupová ◽  
Ivo Šulák ◽  
Jiří Svoboda
Keyword(s):  
High Temperature ◽  
Oxide Dispersion Strengthened ◽  
Step Test ◽  
Coarse Grained ◽  
Fatigue Properties ◽  
Oxide Dispersion ◽  
Ods Alloys ◽  
New Generation ◽  
Near Future ◽  
Ods Alloy

The very recently developed coarse-grained new-generation oxide dispersion strengthened (ODS) alloys containing 5 vol.% homogeneously distributed yttrium nano-precipitates seems to be a promising oxidation-resistant structural material for applications at temperatures above 1000 °C. The primary aim of the present paper is the introduction of the new-generation oxide dispersion strengthened (ODS) alloy and the first testing of its high temperature fatigue properties at 800 °C, concurrently demonstrating a novel and very efficient methodology by using an incremental fatigue step test. The successful application of the methodology motivates the authors to test the fatigue properties of new generation ODS alloys at 1000–1200 °C in the near future.

scholarly journals The Influence of Aluminum Content on Oxidation Resistance of New-Generation ODS Alloy at 1200 °C

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1478 ◽  
Author(s):  
Luděk Stratil ◽  
Vít Horník ◽  
Petr Dymáček ◽  
Pavla Roupcová ◽  
Jiří Svoboda
Keyword(s):  
Oxidation Resistance ◽  
Cross Sections ◽  
Aluminum Content ◽  
Energy Dispersive Spectrometer ◽  
Oxide Dispersion Strengthened ◽  
Xrd Analysis ◽  
Al Content ◽  
Α Al2o3 ◽  
New Generation ◽  
Ods Alloy

The aim of the paper is to evaluate the effect of aluminum content on the oxidation resistance of new-generation of oxide dispersion strengthened (ODS) alloy at 1200 °C. Three grades of the alloy of chemical composition Fe-15Cr-xAl-4Y2O3 with different Al contents x = 0.3 wt.%, 2.0 wt.% and 5.5 wt.% are prepared by mechanical alloying. The alloys are consolidated by high temperature rolling followed by heat treatment. To study the oxidation resistance the samples are isothermally aged in the air for 1 h, 4 h, 16 h and 64 h at 1200 °C. The oxidation kinetics, composition and formation mechanism of the oxide layers are analyzed. The weight gain of prepared steels is estimated. The kinetics of oxidation is studied on metallographic cross-sections of the exposed samples by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analysis. The oxides on the surfaces are identified by X‑ray diffraction (XRD) analysis. The Al content significantly enhances the oxidation resistance of the alloy. For a sufficiently high Al content in the alloy a compact oxide layer of α‑Al2O3 on the surface is formed, which significantly suppresses further oxidation process.

Microstructure of Surface Oxide Films on a Commercial Ods Alloy

1982 ◽  
Vol 40 ◽  
pp. 532-533
Author(s):  
T. A. Ramanarayanan ◽  
M. Raghavan ◽  
R. Petkovic-Luton
Keyword(s):  
Microstructural Analysis ◽  
Microscopic Analysis ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Oxide Interface ◽  
Electron Microscopic ◽  
Temperature Oxidation ◽  
Oxide Adherence ◽  
Ods Alloys ◽  
Ods Alloy

It is well known that the presence of yttria dispersoids in aluminum containing Oxide Dispersion Strengthened (ODS) alloys significantly improve the adherence of the protective AI2O3 oxide scale during high temperature oxidation. However, the exact mechanism by which this improved adherence is brought about is not well understood. As a part of an investigation to study the mechanism of oxide adherence in a ODS alloy MA956, electron microscopic analysis of the oxide and metal/oxide interface was conducted and the results of the microstructural analysis are described here.

Influence of Plastic Deformation on Recrystallized Microstructure of Fe-Base ODS Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 2209-2214
Author(s):  
Carlos Capdevila ◽  
I. Toda ◽  
J. Chao ◽  
Carlos García de Andrés
Keyword(s):  
Plastic Deformation ◽  
Plastic Strain ◽  
Mechanical Alloying ◽  
Recent Work ◽  
Oxide Dispersion Strengthened ◽  
Coarse Grained ◽  
Oxide Dispersion ◽  
Large Influence ◽  
Ods Alloy ◽  
Number Of Authors

The ferritic oxide dispersion strengthened alloys (ODS) are manufactured using the mechanical alloying process. The development of a coarse grained microstructure during the recrystallization has been noted and discussed by a number of authors but, the mechanism of grain control remains uncertain. Recent work has emphasized the large influence of non-uniformities on the development of the recrystallized microstructure. The purpose of the present work was to study the effect of non-uniform plastic strain on recrystallization of Fe-base ODS alloy named MA 957.

scholarly journals Effect of Hot Rolling on the Microstructure and Properties of Nanostructured 15Cr ODS Alloys with Al and Zr Addition

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3695
Author(s):  
Zhengyuan Li ◽  
Lijia Chen ◽  
Haoyu Zhang ◽  
Siqian Zhang ◽  
Zhipeng Zhang ◽  
...  
Keyword(s):  
Hot Rolling ◽  
Hot Isostatic Pressing ◽  
Oxide Dispersion Strengthened ◽  
Large Strains ◽  
High Temperature Strength ◽  
Oxide Dispersion ◽  
Excellent Thermal Stability ◽  
Zr Addition ◽  
Ods Alloys ◽  
Effect Of Hot Rolling

Oxide dispersion strengthened (ODS) alloys with Al and Zr addition have excellent radiation tolerance, high-temperature strength, and corrosion resistance. The 15Cr-Al-Zr-ODS alloys are processed by mechanical alloying (MA), hot isostatic pressing (HIP), subsequent hot rolling to large strains of 70%, and further annealing. The effect of hot rolling on the microstructure, and the properties of nanostructured 15Cr ODS alloys with Al and Zr addition, were investigated. The microstructure after hot rolling and annealing showed obvious anisotropy. The cubic texture (φ1 = 0°, Φ = 0°, φ2 = 0°) {0 0 1} <1 0 0> and brass-R texture (φ1 = 0°, Φ = 55°, φ2 = 45°) {1 1 1} <1 1 0> were observed. The similar size distribution of precipitates was obtained for the comparison of the hot rolling samples with the hot isostatic pressed samples, which can be attributed to excellent thermal stability. After hot rolling, the alloy showed higher yield strength but did not lose too much plasticity.

scholarly journals Effect of Extensive and Limited Plastic Deformation on Recrystallized Microstructure of Oxide Dispersion Strengthened Fe-Cr-Al Alloy

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1052
Author(s):  
Carlos Capdevila ◽  
Rosalia Rementeria ◽  
Maria Aranda ◽  
Javier Vivas ◽  
Jesus Chao ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Mechanical Alloying ◽  
Recent Work ◽  
Grain Growth ◽  
Oxide Dispersion Strengthened ◽  
Coarse Grained ◽  
Al Alloy ◽  
Oxide Dispersion ◽  
Plastic Strains ◽  
Ods Alloy

Ferritic oxide dispersion-strengthened alloys (ODS) are manufactured using a mechanical alloying process. The development of a coarse-grained microstructure during recrystallization has been detected and discussed by several authors, but the mechanism of grain growth remains uncertain. Recent work has emphasized the large influence of non-uniformities on the development of the recrystallized microstructure. The purpose of the present work is to study the effect of both slight heterogeneous plastic strains and strong directional deformation on recrystallization of a ferritic Fe-base ODS alloy.

Annealing Effects on the Microstructure and Thermomechanical Properties of New-Generation ODS Alloys

2020 ◽  
Vol 834 ◽  
pp. 67-74 ◽  
Author(s):  
Omid Khalaj ◽  
Hana Jirková ◽  
Štěpán Jeníček ◽  
Antonín Račický ◽  
Jiří Svoboda
Keyword(s):  
Elevated Temperatures ◽  
Oxide Dispersion Strengthened ◽  
Thermomechanical Properties ◽  
High Temperature Materials ◽  
Annealing Effects ◽  
Similar Materials ◽  
Oxide Particles ◽  
Oxidation Resistant ◽  
Ods Alloys ◽  
New Generation

Recently, the use of high temperature materials are became more common in different types of engineering activities. The new generation of Oxide dispersion strengthened alloys (ODS) consist of Fe-Al matrix with small oxide particles dispersed within it, was generated by the authors to keep their mechanical properties at elevated temperatures. The new ODS prepared by means of mechanical alloying and hot consolidation. The preliminary tests results shows a better oxidation resistant, creep and Ultimate Tensile Strength (UTS) compare to similar materials. To go more inside in thermomechanical and microstructural properties, a series of different test were performed on different variant of ODS which manufactured by the authors. The results show that the annealing time and temperature has a significant influence on these properties while almost total recrystallization of grains and subgrains were observed during the investigation.

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