scholarly journals ODS EUROFER Steel Strengthened by Y-(Ce, Hf, La, Sc, and Zr) Complex Oxides

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1148 ◽  
Author(s):  
Roman Husák ◽  
Hynek Hadraba ◽  
Zdeněk Chlup ◽  
Milan Heczko ◽  
Tomáš Kruml ◽  
...  
Keyword(s):  
Grain Size ◽  
Yield Strength ◽  
Complex Oxides ◽  
Oxide Dispersion Strengthened ◽  
Interparticle Spacing ◽  
Oxide Dispersion ◽  
Strengthening Effect ◽  
Dispersion Strengthening ◽  
Doping Element ◽  
Average Grain Size

Oxide dispersion-strengthened (ODS) materials contain homogeneous dispersions of temperature-stable nano-oxides serving as obstacles for dislocations and further pinning of grain boundaries. The strategy for dispersion strengthening based on complex oxides (Y-Hf, -Zr, -Ce, -La) was developed in order to refine oxide dispersion to enhance the dispersion strengthening effect. In this work, the strengthening of EUROFER steel by complex oxides based on Y and elements of the IIIB group (lanthanum, scandium) and IVB group (cerium, hafnium, zirconium) was explored. Interparticle spacing as a dispersoid characteristic appeared to be an important factor in controlling the dispersion strengthening contribution to the yield strength of ODS EUROFER steels. The dispersoid size and average grain size of ODS EUROFER steel were altered in the ranges of 5–13 nm and 0.6–1.7 µm, respectively. Using this strategy, the yield strength of the prepared alloys varied between 550 MPa and 950 MPa depending on the doping element.

scholarly journals Microstructure and Enhanced Properties of Copper-Vanadium Nanocomposites Obtained by Powder Metallurgy

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 339 ◽  
Author(s):  
Yong Wang ◽  
Jinguo Wang ◽  
Haohao Zou ◽  
Yutong Wang ◽  
Xu Ran
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Yield Strength ◽  
Grain Boundary ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Copper Matrix ◽  
Dispersion Strengthening ◽  
Annealed Copper ◽  
Grain Boundary Strengthening

Cu-2.4 wt.%V nanocomposite has been prepared by mechanical alloy and vacuum hot-pressed sintering technology. The composites were sintered at 800 °C, 850 °C, 900 °C, and 950 °C respectively. The microstructure and properties of composites were investigated. The results show that the Cu-2.4 wt.%V composite presents high strength and high electrical conductivity. The composite sintered at 900 °C has a microhardness of 205 HV, a yield strength of 404.41 MPa, and an electrical conductivity of 79.5% International Annealed Copper Standard (IACS); the microhardness and yield strength reduce gradually with the increasing consolidation temperature, which is mainly due to the growth of copper grain size. After sintering, copper grain size and V nanoparticle both maintain in nanoscale; the strengthening mechanism is related to grain boundary strengthening and dispersion strengthening, while the grain boundary strengthening mechanism plays the most important role. This study indicates that the addition of small amounts of V element could enhance the copper matrix markedly with the little sacrifice of electrical conductivity.

scholarly journals A 2.9 GPa Strength Nano-Grained and Nano-Precipitated 304L-Type Austenitic Stainless Steel

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5382
Author(s):  
Congcong Du ◽  
Guoying Liu ◽  
Baoru Sun ◽  
Shengwei Xin ◽  
Tongde Shen
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Yield Strength ◽  
Average Particle Size ◽  
Coarse Grained ◽  
Average Particle ◽  
Dispersion Strengthening ◽  
Ultrafine Grained ◽  
Average Grain Size ◽  
Bulk Nanocrystalline

Austenitic stainless steel has high potential as nuclear and engineering materials, but it is often coarse grained and has relatively low yield strength, typically 200–400 MPa. We prepared a bulk nanocrystalline lanthanum-doped 304L austenitic stainless steel alloy by a novel technique that combines mechanical alloying and high-pressure sintering. The achieved alloy has an average grain size of 30 ± 12 nm and contains a high density (~1024 m−3) of lanthanum-enriched nanoprecipitates with an average particle size of approx. 4 nm, leading to strong grain boundary strengthening and dispersion strengthening effects, respectively. The yield strength of nano-grained and nano-precipitated stainless steel reaches 2.9 GPa, which well exceeds that of ultrafine-grained (100–1000 nm) and nano-grained (<100 nm) stainless steels prepared by other techniques developed in recent decades. The strategy to combine nano-grain strengthening and nanoprecipitation strengthening should be generally applicable to developing other ultra-strong metallic alloys.

scholarly journals Enhanced Mechanical Properties of Mg-6Sn-3Al-1Zn Alloy with Bimodal Grain Size Disturbed in the Microstructure Uniformly through Changing the Rolling Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Fuan Wei ◽  
Jinhui Wang ◽  
Ping Li ◽  
Bo Shi
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Volume Fraction ◽  
Rolling Temperature ◽  
Average Grain Size ◽  
Small Grains ◽  
Mg2sn Phase ◽  
Average Size ◽  
Bimodal Grain Size

The mechanical properties of Mg-6Sn-3Al-1Zn alloy were enhanced with bimodal grain size disturbed in the microstructure uniformly; the Mg-6Sn-3Al-1Zn alloys were rolled with 60% thickness reduction at different rolling temperatures. The results have shown that the Mg-6Sn-3Al-1Zn alloys are composed of Mg2Sn phase and α-Mg matrix phase. When the rolling temperature was less than or equal to 400°C, with the rolling temperature increasing, the average size and volume fraction of Mg2Sn phase and the average grain size of small grains remained unchanged, the average grain size of large grains decreased, the volume fraction of small grains increased, and the yield strength of the alloy increased. When the rolling temperature reached 450°C, the average size and volume fraction of Mg2Sn phase and the average grain size of large grains increased, and the volume fraction of small grains and the yield strength of the alloy decreased. The elongation increased with the rolling temperature increasing, but the change trend of hardness was just opposite. When the alloy was rolled at 400°C, the average sizes of small grains, large grains, and Mg2Sn phases were 3.66 μm, 9.24 μm, and 19.5 μm, respectively. The volume fractions of small grains, large grains, and Mg2Sn phases were 18.6%, 77.6%, and 3.8%, respectively. And the tensile properties reached the optimum; for example, the tensile strength, yield strength, elongation, and Vickers hardness were 361 MPa, 289.5 MPa, 20.5%, and 76.3 HV, respectively.

scholarly journals Effect of Heat Treatment on Mechanical Properties and Microstructure Morphology of Low-Alloy High-Strength Steel

2016 ◽  
Vol 61 (2) ◽  
pp. 475-480
Author(s):  
K. Bolanowski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
High Strength Steel ◽  
High Strength ◽  
Strengthening Phase ◽  
Average Grain Size

Abstract The paper analyzes the influence of different heat treatment processes on the mechanical properties of low-alloy high-strength steel denoted by Polish Standard (PN) as 10MnVNb6. One of the findings is that, after aging, the mechanical properties of rolled steel are high: the yield strength may reach > 600 MPa, and the ultimate tensile strength is > 700 MPa. These properties are largely dependent on the grain size and dispersion of the strengthening phase in the ferrite matrix. Aging applied after hot rolling contributes to a considerable rise in the yield strength and ultimate tensile strength. The process of normalization causes a decrease in the average grain size and coalescence (reduction of dispersion) of the strengthening phase. When 10MnVNb6 steel was aged after normalization, there was not a complete recovery in its strength properties.

Effect of Bi on Microstructure and Mechanical Properties of Extruded AZ80-2Sn Magnesium Alloy

2018 ◽  
Vol 37 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Hansong Xue ◽  
Xinyu Li ◽  
Weina Zhang ◽  
Zhihui Xing ◽  
Jinsong Rao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Magnesium Alloy ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Microstructure And Mechanical Properties ◽  
Average Grain Size

AbstractThe effects of Bi on the microstructure and mechanical properties of AZ80-2Sn alloy were investigated. The results show that the addition of Bi within the as-cast AZ80-2Sn alloy promotes the formation of Mg3Bi2 phase, which can refine the grains and make the eutectic phases discontinuous. The addition of 0.5 % Bi within the as-extruded AZ80-2Sn alloy, the average grain size decreases to 12 μm and the fine granular Mg17Al12 and Mg3Bi2 phases are dispersed in the α-Mg matrix. With an increase in Bi content, the Mg17Al12 and Mg3Bi2 phases become coarsened and the grain size increases. The as-extruded AZ80-2Sn-0.5 %Bi alloy has the optimal properties, and the ultimate tensile strength, yield strength and elongation are 379.6 MPa, 247.1 MPa and 14.8 %, respectively.

Microstructure and Mechanical Properties of Mg96Y3Zn1 Alloy Processed by Equal Channel Angular Pressing

2011 ◽  
Vol 682 ◽  
pp. 49-54
Author(s):  
Bin Chen ◽  
Chen Lu ◽  
Dong Liang Lin ◽  
Xiao Qin Zeng
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Equal Channel Angular Pressing ◽  
Ultrafine Grains ◽  
Angular Pressing ◽  
Average Grain Size

The Mg96Y3Zn1 alloy processed by equal channel angular pressing has been investigated. It was found that the Mg96Y3Zn1 alloy processed by ECAP obtained ultrafine grains and exhibits excellent mechanical properties. After ECAP, the average grain size of Mg96Y3Zn1 alloy refined to about 400 nm. The highest strengths with yield strength of 381.45MPa and ultimate tensile strength of 438.33MPa were obtained after 2 passes at 623K. It was found that cracks were preferentially initiated and propagated in the interior of X-phase during the tensile test. As a result, the elongation of alloy is decreased with pass number increasing.

scholarly journals Material Assessment of Canadian SAW Line-Pipes

1998 ◽  
Author(s):  
D. K. Mak ◽  
W. R. Tyson
Keyword(s):  
Fracture Toughness ◽  
Grain Size ◽  
Yield Strength ◽  
Notch Toughness ◽  
J Integral ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Ductile Tearing ◽  
Average Grain Size ◽  
Grade One

Eight pipes, manufactured between 1952 and 1981, have been collected from various Canadian pipeline companies and tested. They include six pipes from the field made in the 1950’s and 1960’s of X52 grade, one experimental pipe manufactured in the early 1970’s of X65 grade, and a modern clean steel of X70 grade manufactured in 1981. The steels have been characterized by chemical composition, grain size, yield and tensile strengths, notch toughness (Charpy V-notch absorbed energy), and fracture toughness (J-integral and crack-tip opening displacement). The modern steel has much lower carbon content and much smaller grain size compared to the pipes manufactured in the 1950’s and 1960’s. The former is a fully-killed controlled-rolled steel while the latter are semi-killed ferrite-pearlite steels. All eight pipes have ferrite-pearlite microstructures, with the average grain size ranging from 4 to 14 μm. The transverse yield strength was found to be significantly higher (by about 20%) than the longitudinal yield strength. Notch toughness and fracture toughness were similar for pipes manufactured in the 1950’s and 1960’s. In comparison, the modern steel has much higher toughness and higher strength. J-integral and CTOD δ were found to be related by J = m σyδ with m = 1.8 and σy the transverse yield strength. The J-integral at 0.2 mm crack growth was consistent with a linear correlation with the upper-shelf Charpy energy. All the steels in this study fractured by ductile tearing in slow loading in spite of the low toughness of the older steels. It is suggested that, in the absence of Charpy upper shelf data, a reasonable representative toughness for resistance to axial surface flaws propagating by ductile tearing is J = 120±15 kJ/m2.

Excessive ThO2 Particle Growth in Ni-2ThO2 at High Temperature

1970 ◽  
Vol 28 ◽  
pp. 416-417
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
Particle Size ◽  
Metal Matrix ◽  
Oxide Dispersion Strengthened ◽  
Particle Growth ◽  
Interparticle Spacing ◽  
Refractory Oxide ◽  
Oxide Dispersion ◽  
Volume Percent ◽  
Oxide Particles ◽  
Cold Worked

It is generally accepted that a uniform spatial distribution of fine refractory oxide particles is required in an oxide-dispersion-strengthened metal to provide good elevated-temperature strengths. The presence of these particles stabilizes the cold-worked microstructure by anchoring low-angle cell boundaries and by restricting the motion of dislocations during loading. Such action by the particles must be a function of the interparticle spacing as is proposed by the Orowan model for yield stress. For a given volume percent of oxide in the metal matrix, the interparticle spacing is directly proportional to the particle size. Therefore, particle growth during the processing of oxide-dispersion-strengthened metals increases the interparticle spacing and inherently decreases the strength.

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