Dispersion behaviour of oxide particles in mechanically alloyed ODS steel

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.

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Production of Oxide Dispersion Strengthened Mg-Zn-Y Alloy by Equal Channel Angular Pressing of Mechanically Alloyed Powder

Metals ◽

10.3390/met10050679 ◽

2020 ◽

Vol 10 (5) ◽

pp. 679 ◽

Cited By ~ 1

Author(s):

Keng-Liang Ou ◽

Chia-Chun Chen ◽

Chun Chiu

Keyword(s):

Equal Channel Angular Pressing ◽

Oxide Dispersion Strengthened ◽

Oxide Dispersion ◽

Dispersion Strengthening ◽

Mechanically Alloyed ◽

Angular Pressing ◽

Lpso Structure ◽

Gas Atmosphere ◽

Solution Strengthening ◽

Oxide Particles

Mg-Zn-Y alloys with long-period stacking ordered structures (LPSO) have attracted attention due to their excellent mechanical properties. In addition to the LPSO structure, Mg alloys can also be strengthened by oxide particles. In the present study, oxide dispersion strengthened Mg97Zn1Y2 (at%) alloys were prepared by equal channel angular pressing (ECAP) of mechanical alloyed (MA) powder under an oxygen gas atmosphere. The 20-h-MA powder had a particle size of 28 μm and a crystallite size of 36 nm. During the MA process followed by ECAP, an Mg matrix with dispersed Y2O3 (and MgO) particles was formed. The alloy processed by ECAP exhibited a hardness of 110 HV and a compressive strength of 185 MPa. Compared to pure Mg, the increased hardness was due to the dispersion strengthening of Y2O3 and MgO particles and solution strengthening of Zn and Y.

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Atom probe tomography analysis of Ti-Y-O clustering during processing of nanoscale oxide particles in 14%Cr ODS ferritic steels

MRS Proceedings ◽

10.1557/opl.2011.328 ◽

2011 ◽

Vol 1298 ◽

Cited By ~ 1

Author(s):

Ceri A. Williams ◽

Paulina Unifantowicz ◽

Zbigniew Oksiuta ◽

Nadine Baluc ◽

George D. W. Smith ◽

...

Keyword(s):

Atom Probe Tomography ◽

Atom Probe ◽

Ferritic Steels ◽

Ods Steel ◽

Atom Probe Tomography Analysis ◽

Oxide Particles ◽

Tomography Analysis

ABSTRACTAtom probe tomography is used to investigate the clustering of Y-Ti-O in a 14%Cr-2%W-0.3%Ti & 0.3% Y2O3 ODS steel. The clusters in the consolidated material are compared to clusters observed in the powder prior to consolidation. A higher density of smaller clusters is observed in the powder, and the clusters are found to contain more O and less Y.

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Stability of oxide particles under electron irradiation in a 9Cr ODS steel at 400 °C

Journal of Nuclear Materials ◽

10.1016/j.jnucmat.2014.09.011 ◽

2014 ◽

Vol 455 (1-3) ◽

pp. 724-727 ◽

Cited By ~ 12

Author(s):

Feng Li ◽

Hiroaki Abe ◽

Takahiro Ishizaki ◽

Yanfen Li ◽

Takuya Nagasaka ◽

...

Keyword(s):

Electron Irradiation ◽

Ods Steel ◽

Oxide Particles

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Evolution of Oxide Particles during Fabrication Processes of 12Cr ODS Steel

MRS Proceedings ◽

10.1557/opl.2012.687 ◽

2012 ◽

Vol 1383 ◽

Author(s):

Xiaodong Mao ◽

Tae Kyu Kim ◽

Sung-Soo Kim ◽

Chang Hee Han ◽

Kyu Hwan Oh ◽

...

Keyword(s):

Hot Rolling ◽

Rolling Process ◽

Face Centered Cubic ◽

Metal Powders ◽

Heat Treated Sample ◽

Ods Steel ◽

Treated Sample ◽

The Matrix ◽

Oxide Particles ◽

Face Centered

ABSTRACT12Cr ODS steel samples were prepared by mechanical alloying of the metal powders with 20-30 nm Y2O3 particles followed by isostatic pressing, hot rolling and final heat treatment. Evolutions of oxide particles such as YTaO4 and YCrO3 after each fabrication step were investigated by using TEM with EDS. Crystallographic correlation between oxide particles and the matrix was investigated in a HIPped sample, and interactions between dislocations and oxide particles were observed in hot rolled or heat treated sample. Size distributions of oxide particles were measured by carbon replica samples and it was found that coarsening of oxide particles from 9 to 12 nm occurred during hot rolling process. Additional isothermal annealing at 1250 ˚C revealed that phase transformation of oxide particles from monoclinic YTaO4 to face centered cubic Y3TaO7 was observed.

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Structural Evolution of Nano-sized Oxide Particles Formed in Mechanically Alloyed Fe-10Cr-5Y2O3 Powders

Metals ◽

10.3390/met10030310 ◽

2020 ◽

Vol 10 (3) ◽

pp. 310

Author(s):

Ga Eon Kim ◽

Tae Kyu Kim ◽

Sanghoon Noh

Keyword(s):

Heat Treatment ◽

Phase Transformation ◽

Mechanical Alloying ◽

Morphological Change ◽

Ball Mill ◽

Structural Evolution ◽

Oxide Phase ◽

High Energy ◽

Mechanically Alloyed ◽

Oxide Particles

Fe-10Cr-5Y2O3 powders were mechanically alloyed using a high energy horizontal ball-mill apparatus, and the effect of heat treatment on the behavior of nano-sized oxide particles formed in the mechanically alloyed Fe-10Cr-5Y2O3 powders was investigated. Elongated Cr-rich and Y-rich oxides were observed in the mechanically alloyed powders. During the heating of these powders above 700 °C, the elongated Cr-rich oxides were dramatically changed to a near- spherical morphology. Cubic-Y2O3, monoclinic-Y2O3 and YFeO3 phases were also found after heat treatment at 1150 °C for 1h, indicating that the Y-rich oxide phase was transformed to the cubic-Y2O3, monoclinic-Y2O3 and YFeO3 ones. It is thus concluded that both a morphological change of Cr-rich oxide and a phase transformation of Y-rich oxide during the heating of mechanically alloyed powders could be mainly attributed to extremely high energy, accumulated by the mechanical alloying process.

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A Precipitation Behavior of Nano-Oxide Particles in Mechanically Alloyed Fe-5Y2O3Powders

Journal of Korean Powder Metallurgy Institute ◽

10.4150/kpmi.2015.22.1.46 ◽

2015 ◽

Vol 22 (1) ◽

pp. 46-51 ◽

Cited By ~ 1

Author(s):

Ga Eon Kim ◽

Sanghoon Noh ◽

Ji Eun Choi ◽

Young Do Kim ◽

Tae Kyu Kim

Keyword(s):

Precipitation Behavior ◽

Mechanically Alloyed ◽

Nano Oxide ◽

Oxide Particles

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Microstructure and Mechanical Properties of Mechanically Alloyed NiAl

MRS Proceedings ◽

10.1557/proc-213-661 ◽

1990 ◽

Vol 213 ◽

Cited By ~ 4

Author(s):

S. J. Hwang ◽

P. Nash ◽

M. Dollar ◽

S. Dymek

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Dislocation Density ◽

Work Hardening ◽

Room Temperature ◽

Hot Extrusion ◽

Homogeneous Distribution ◽

Mechanically Alloyed ◽

Oxide Particles ◽

Temperature Work

ABSTRACTMechanical alloying (MA) has been used to produce NiAl powders from either elemental or prealloyed constituents. The powders were consolidated by hot extrusion resulting in material which was fully dense, with a grain size around 1 μm and a homogeneous distribution of oxide particles with sizes in the range 10 to 100 nm. TEM observation indicates the presence of a significant dislocation density after consolidation. Mechanical properties have been studied by compression testing from room temperature to 1300 K in air. Yield strengths ranged from 1453 MPa to 32 MPa depending on material and test temperature. Work hardening was observed at all test temperatures for both materials. Substantial ductility was observed even at room temperature where it exceeds 7.5 %. The effects of microstructure on the mechanical properties are discussed.

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