Phenomena Leading to a Modification of the Nano-Sized Structure during Resistance Upset Welding of ODS Steel Cladding

2012 ◽  
Vol 706-709 ◽  
pp. 977-982 ◽  
Author(s):  
Fabien Corpace ◽  
A. Monnier ◽  
A. Poulon Quintin ◽  
J P. Manaud
Keyword(s):  
Mechanical Properties ◽  
Welding Process ◽  
Oxide Dispersion Strengthened ◽  
Fusion Welding ◽  
Oxide Dispersion ◽  
Fuel Cladding ◽  
Ods Steel ◽  
The Matrix ◽  
Ods Steels ◽  
Two Stages

ODS steels (Oxide Dispersion Strengthened) are candidate materials for fuel cladding in Sodium Fast Reactors (SFR). These materials have good mechanical properties at high temperature due to a dispersion of nanometer-sized oxides into the matrix. Previous studies have shown that melting can induce a decrease of the mechanical properties at high temperatures due to modifications of the nanometer-sized oxide dispersion. Therefore the fusion welding techniques are not recommended and the solid state boundings has to be evaluated. This study is focused on resistance upset welding. Welding experiments and numerical simulations are coupled. The numerical simulation is developed in order to have a better understanding of the thermal and the mechanical phenomena occurring during the welding process. The simulation shows that the welding steps can be divided in two stages. First, the temperature of the contact between pieces increases. Second, the heat generation is mainly located in the cladding leading to the collapse and forging the pieces. The microstructural observations confirm that the major deformation is located in the cladding. Oxide dispersion modification and dynamical recrystallisation has been found for welds achieved with a non optimized process parameter set. The deformation and the temperature seem to be of prime importance in the modification of the oxide dispersion.

scholarly journals Microstructure and Mechanical Properties of 14Cr-ODS Steels with Zr Addition

2019 ◽  
Vol 38 (2019) ◽  
pp. 404-410 ◽  
Author(s):  
Weijuan Li ◽  
Haijian Xu ◽  
Xiaochun Sha ◽  
Jingsong Meng ◽  
Zhaodong Wang
Keyword(s):  
Mechanical Properties ◽  
Hot Isostatic Pressing ◽  
Oxide Dispersion Strengthened ◽  
Nominal Composition ◽  
Ods Steel ◽  
Zr Addition ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Ods Steels ◽  
The Impact

AbstractIn this study, oxide dispersion strengthened (ODS) ferritic steels with nominal composition of Fe–14Cr–2W–0.35Y2O3 (14Cr non Zr-ODS) and Fe–14Cr–2W–0.3Zr–0.35Y2O3 (14Cr–Zr-ODS) were fabricated by mechanical alloying (MA) and hot isostatic pressing (HIP) technique to explore the impact of Zr addition on the microstructure and mechanical properties of 14Cr-ODS steels. Microstructure characterization revealed that Zr addition led to the formation of finer oxides, which was identified as Y4Zr3O12, with denser dispersion in the matrix. The ultimate tensile strength (UTS) of the non Zr-ODS steel is about 1201 MPa, but UTS of the Zr-ODS steel increases to1372 MPa, indicating the enhancement of mechanical properties by Zr addition.

scholarly journals Effect of Small Variations in Zr Content on the Microstructure and Properties of Ferritic ODS Steels Consolidated by SPS

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 348 ◽  
Author(s):  
Andrea García-Junceda ◽  
Eric Macía ◽  
Dariusz Garbiec ◽  
Marta Serrano ◽  
José M. Torralba ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Heating Rates ◽  
Ultrafine Grains ◽  
Ods Steel ◽  
Plasma Sintering ◽  
Final Microstructure ◽  
Spark Plasma ◽  
Ods Steels

Two different zirconium contents (0.45 and 0.60 wt.%) have been incorporated into a Fe-14Cr-5Al-3W-0.4Ti-0.25Y2O3 oxide dispersion-strengthened (ODS) steel in order to evaluate their effect on the final microstructure and mechanical properties. The powders with the targeted compositions were obtained by mechanical alloying (MA), and subsequently processed by spark plasma sintering (SPS) at two different heating rates: 100 and 400 °C·min−1. Non-textured bimodal microstructures composed of micrometric and ultrafine grains were obtained. The increase in Zr content led to a higher percentage of Zr nano-oxides and larger regions of ultrafine grains. These ultrafine grains also seem to be promoted by higher heating rates. The effective pinning of the dislocations by the Zr dispersoids, and the refining of the microstructure, have significantly increased the strength exhibited by the ODS steels during the small punch tests, even at high temperatures (500 °C).

scholarly journals Microstructure of Oxide Dispersion Strengthened Steel With Cr Content Variation

2020 ◽  
Vol 21 (1) ◽  
pp. 35
Author(s):  
Marzuki Silalahi ◽  
Bernadus Bandriyana ◽  
Arbi Dimyati ◽  
Bambang Sugeng ◽  
Syahfandi Ahda ◽  
...  
Keyword(s):  
High Temperature ◽  
Phase Distribution ◽  
Oxide Dispersion Strengthened ◽  
High Energy ◽  
Oxide Dispersion ◽  
X Ray ◽  
Hardness Tester ◽  
Cr Content ◽  
Ods Steel ◽  
The Matrix

Microstructure and phase distribution of innovative Oxide Dispersion Strengthened (ODS) steel based on Fe-Cr-ZrO2 particularly for application at high temperature reactor with variation of Cr content was analysed. The alloy was synthesized with Cr composition variation of  15, 20 and 25 wt.% Cr, while zirconia dispersoid kept constant at 0.50 wt.%. The samples was synthesized by mechanical alloying comprising of high energy milling for 3 hours followed by vibrated compression with iso-static load at 20 ton. The final consolidation was performed via sintering process for 4 minutes using the Arc Plasma Sintering (APS) technique, a new method developed in BATAN especially for synthesizing high temperature materials. The samples were then characterized by means of scanning electron microscopy (SEM) with energy dispersed X-ray (EDX) analysis capability and X-ray diffraction. The mechanical property of hardness was measured using standard Vickers micro hardness tester to confirmed the microstructure analysis.  The results show that the microstructure of the ODS alloy samples in all variation of Cr content consists generally of cubic Fe-Cr matrix phase with small of porosity and  Zirconia particles distributed homogenously in and around the matrix grains. The achievable hardness was between 142 and 184 HVN dependent consistently on Cr content in which Cr element may cause grain refining that in turn increase the hardness.

scholarly journals Development of New 14 Cr ODS Steels by Using New Oxides Formers and B as an Inhibitor of the Grain Growth

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1344
Author(s):  
Alberto Meza ◽  
Eric Macía ◽  
Andrea García-Junceda ◽  
Luis Antonio Díaz ◽  
Paul Chekhonin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Growth ◽  
Electron Backscatter Diffraction ◽  
Oxide Dispersion Strengthened ◽  
Complex Oxide ◽  
Tensile Tests ◽  
Processing Route ◽  
Prealloyed Powder ◽  
Ods Steel ◽  
Ods Steels

In this work, new oxide dispersion strengthened (ODS) ferritic steels have been produced by powder metallurgy using an alternative processing route and characterized afterwards by comparing them with a base ODS steel with Y2O3 and Ti additions. Different alloying elements like boron (B), which is known as an inhibitor of grain growth obtained by pinning grain boundaries, and complex oxide compounds (Y-Ti-Zr-O) have been introduced to the 14Cr prealloyed powder by using mechanical alloying (MA) and were further consolidated by spark employing plasma sintering (SPS). Techniques such as x-ray diffraction (XRD), electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM) were used to study the obtained microstructures. Micro-tensile tests and microhardness measurements were carried out at room temperature to analyze the mechanical properties of the differently developed microstructures, which was considered to result in a better strength in the ODS steels containing the complex oxide Y-Ti-Zr-O. In addition, small punch (SP) tests were performed to evaluate the response of the material under high temperatures conditions, under which promising mechanical properties were attained by the materials containing Y-Ti-Zr-O (14Al-X-ODS and 14Al-X-ODS-B) in comparison with the other commercial steel, GETMAT. The differences in mechanical strength can be attributed to the precipitate’s density, nature, size, and to the density of dislocations in each ODS steel.

Austenitic Oxide Dispersion Strengthened Steels : A Review

2016 ◽  
Vol 66 (4) ◽  
pp. 316 ◽  
Author(s):  
Lavanya Raman ◽  
Karthick Gothandapani ◽  
B.S. Murty
Keyword(s):  
Oxide Dispersion Strengthened ◽  
Current Status ◽  
Oxide Dispersion ◽  
Hard Particles ◽  
Void Swelling ◽  
The Matrix ◽  
Swelling Characteristics ◽  
Ods Steels ◽  
Breeder Reactors ◽  
Materials Used

Materials play an important role in the fast breeder reactors.  Materials used in cladding tube and fuel pins should have better creep and void swelling resistance. To overcome these difficulties, a new class of material known as oxide dispersion strengthened (ODS) steels are used. There are two groups of ODS steels, the ferritic and the austenitic ODS steels based on the matrix. The present paper reviews the current status of research in austenitic ODS steels. The interaction of dislocations with finely dispersed incoherent, hard particles that governs the strength and high temperature properties of ODS materials is briefly reviewed. The synthesis route adopted for these ODS steels, which is mostly through powder metallurgy route is also discussed. The role of various oxides such as Y2O3, ZrO2and TiO2and the clusters formed in these ODS steels on the mechanical properties and void swelling characteristics is also discussed.

scholarly journals Manufacturing Oxide Dispersion-Strengthened (ODS) Steel Fuel Cladding Tubes Using the Cold Spray Process

JOM ◽  
2019 ◽  
Vol 71 (8) ◽  
pp. 2868-2873 ◽  
Author(s):  
Mia Lenling ◽  
Hwasung Yeom ◽  
Benjamin Maier ◽  
Greg Johnson ◽  
Tyler Dabney ◽  
...  
Keyword(s):  
Cold Spray ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Fuel Cladding ◽  
Cold Spray Process ◽  
Spray Process ◽  
Ods Steel

Creep Behavior and Microstructure of 8Cr Oxide Dispersion Strengthened Martensitic Steel

2010 ◽  
Vol 638-642 ◽  
pp. 2309-2314
Author(s):  
Kei Shinozuka ◽  
Hisao Esaka ◽  
M. Tamura ◽  
Hiroyasu Tanigawa
Keyword(s):  
Creep Deformation ◽  
Rolling Direction ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Martensitic Steels ◽  
Creep Tests ◽  
Nuclear Fusion Reactor ◽  
Ods Steel ◽  
Temperature Oxide ◽  
Ods Steels

In international thermonuclear experimental reactor (ITER), reduced activation ferritic/martensitic steels will be used for plasma-facing materials. However, it is necessary to raise the temperature of operation in order to elevate efficiency of electric power generation by using the material which is more excellent in strength at elevated temperature. Oxide dispersion strengthened (ODS) steels are promising candidate for high temperature materials of a nuclear fusion reactor. There are many reports that ODS steels show very high creep strength, but there are few reports on creep deformation mechanism. In this work, creep deformation behavior of 8 wt% Cr ODS steel was investigated. This ODS steel had high density of fine dispersed Y2Ti2O7 particles and -ferrite grains elongated along the hot-rolling direction. The creep curve showed a low creep strain rate until specimen ruptured. Vickers hardness of the gauge part of specimens in interrupted creep tests decreased with increasing the loading time. However, that of the grip part did not change significantly. Accordingly, although dynamic recovery occurred in the ODS steel, it had not affected the creep deformation rate.

Oxidation of Oxide Dispersion Strengthened Steels: II. Kinetics and Mechanism

2013 ◽  
Vol 748 ◽  
pp. 106-111
Author(s):  
Jae Hoon Lee
Keyword(s):  
Grain Refinement ◽  
Oxidation Resistance ◽  
Oxide Dispersion Strengthened ◽  
Oxide Dispersion ◽  
Protective Oxide ◽  
Alumina Layer ◽  
Ods Steel ◽  
Time Period ◽  
Oxide Particles ◽  
Ods Steels

The oxidation resistance of 18%Cr-oxide dispersion strengthened (ODS) ferritic steels with and without 5%Al has been investigated in air at 700900 °C for time period up to 540 h. The oxidation rate of ODS steels is significantly dependent on the oxidation time and temperature. Compared to Al-containing ODS steel, the finer grains of Al-free ODS steel are due to the formation of smaller coherent oxide particles which suppress the steel's grain growth. The grain refinement of ODS steels is expected to allow rapid segregation of Cr or Al to the steel surface, so that the continuous Fe-Cr spinel or alumina layer is formed quickly in comparison to the alloys without oxide particles dispersion. Therefore, the excellent oxidation resistance of ODS steels is owing to the formation of continuous, protective oxide layers which correlate with oxide nanoparticles and grain refinement.

scholarly journals Effect of Oxygen Content on Microstructure and Tensile Properties of a 22Cr-5Al ODS Steel

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2241
Author(s):  
Yukun Zhang ◽  
Yingjie Yan ◽  
Yazhong Zhai ◽  
Wei Qin ◽  
Hongyan Che ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Grain Boundaries ◽  
Oxygen Content ◽  
Hot Isostatic Pressing ◽  
Oxide Dispersion Strengthened ◽  
Ods Steel ◽  
The Matrix ◽  
Ods Steels ◽  
Effect Of Oxygen ◽  
Content Of Oxygen

The high tensile strength and irradiation resistance of oxide dispersion strengthened (ODS) ferritic steels is attributed to the ultrafine and dispersed oxides within the matrix. The high content of oxygen and yttrium is critical for the formation of dense Y-rich oxides. However, only few studies have reported the effect of oxygen content on the microstructure and mechanical properties of ODS steels. Herein, we employed gas atomization reactive synthesis to prepare pre-alloy powders and then hot isostatic pressing (HIP) to consolidate two 22Cr-5Al ODS steels with different oxygen content. Our results showed Y-rich precipitates at and near grain boundaries of the as-HIPed alloys. Moreover, with the oxygen content increasing from 0.04 to 0.16 wt%, more precipitates precipitated in the as-HIPed alloy, and the ultimate tensile strength of the alloy was improved. However, increasing the oxygen content to 0.16 wt% led to formation of stripe and chain precipitates at and near grain boundaries, which caused a partial intergranular fracture of the as-HIPed alloy.

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