Effect of Ni on Microstructure and Mechanical Properties of Bulk Nanocrystalline Fe-Al Based Alloys Prepared by Aluminothermic Reaction

2013 ◽  
Vol 745-746 ◽  
pp. 715-721 ◽  
Author(s):  
Pei Qing La ◽  
Yu Peng Wei ◽  
Yang Yang ◽  
Hong Ding Wang ◽  
Ya Ping Bai
Keyword(s):  
Solid Solution ◽  
Yield Strength ◽  
Coarse Grained ◽  
Compressive Yield Strength ◽  
Electron Probe Microanalyzer ◽  
Aluminothermic Reaction ◽  
Transmission Electron ◽  
The Matrix ◽  
Bulk Nanocrystalline ◽  
20 Nm

Bulk nanocrystalline Fe-Al based alloys with 5, 10 and 15 wt. % Ni were prepared by aluminothermic reaction. The alloys were analyzed by electron probe microanalyzer, X-ray diffraction and transmission electron microscope. Compressive yield strength and hardness of the alloys were tested. The experimental results showed that all of the alloys consisted of Fe-Al-Ni matrix and small amount of Al2O3 sphere. The matrix phases of the alloys with 5 and 10 wt. % Ni had disordered α-Fe solid solution, while the matrix phases of the alloys with 15 wt. % Ni had disordered α-Fe solid solution, NiAl phase and Fe3AlCx phase. Average grain sizes of the matrix phases of the alloys were about 20 nm. The alloys with 5 wt.% Ni had the best plasticity, but the alloys with 15 wt. % Ni had the highest yield strength and hardness. Yield strength of those alloys is higher than that of coarse-grained Fe3Al.

Microstructures and Mechanical Properties of Bulk Nanocrystalline Fe3Al Materials With 5, 10 and 15 wt. % Cu Prepared by Aluminothermic Reaction

2011 ◽  
Vol 236-238 ◽  
pp. 2191-2196 ◽  
Author(s):  
Yu Peng Wei ◽  
Pei Qing La ◽  
Mei Dan Que ◽  
Wen Sheng Li ◽  
Yang Yang ◽  
...  
Keyword(s):  
Yield Strength ◽  
Optical Microscope ◽  
Matrix Phase ◽  
Coarse Grained ◽  
Compressive Yield Strength ◽  
Nanocrystalline Phase ◽  
X Ray Diffraction ◽  
Aluminothermic Reaction ◽  
Transmission Electron ◽  
Bulk Nanocrystalline

Bulk nanocrystalline Fe3Al based materials with 5, 10 and 15 wt. % Cu were prepared by aluminothermic reaction in which the melts were superheated about 1600 K before solidification. Microstructures of those materials were investigated by optical microscope, electron probe microanalysis, X-ray diffraction and transmission electron microscope. It was shown that microstructures of the materials consisted of a nanocrystalline matrix phase and a little contamination Al2O3and Fe3AlCxfiber phases. The nanocrystalline matrix phase was composed of Fe, Al and Cu elements and disordered bcc which did not change with content of Cu. Average grain sizes of the nanocrystalline phase of the materials with 5, 10 and 15 wt. % Cu were 18, 24 and 25 nm respectively and that of the material with 5 wt. % Cu was the smallest. Compressive properties of the materials were tested. The material with 5 wt. % Cu has good ductility compared with the materials with 10 and 15 wt. % Cu. Yield strength of the materials was about two times higher than that of coarse grained Fe3Al material. The compressive yield strength of the material with 5 wt. % Cu was higher than those of the materials with 10 and 15 wt. % Cu and its flow stress in compression was up to about 1500 MPa.

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.

Nanoporous Ni and Ni-Cu Fabricated by Dealloying

2009 ◽  
Vol 1228 ◽  
Author(s):  
Masataka Hakamada ◽  
Yasumasa Chino ◽  
Mamoru Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Noble Metals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Difference ◽  
20 Nm ◽  
Good Workability ◽  
Scanning Electron

AbstractMetallic nanoporous architecture can be spontaneously attained by dealloying of a binary alloy. The nanoporous architecture can be often fabricated in noble metals such as Au and Pt. In this study, nanoporous Ni, Ni-Cu are fabricated by dealloying rolled Ni-Mn and Cu-Ni-Mn alloys, respectively. Unlike conventional Raney nickel composed of brittle Ni-Al or Cu-Al intermetallic compounds, the initial alloys had good workability probably because of their fcc crystal structures. After the electrolysis of the alloys in (NH4)2SO4 aqueous solution, nanoporous architectures of Ni and Ni-Cu with pore and ligament sizes of 10–20 nm were confirmed by scanning electron microscopy and transmission electron microscopy. X-ray diffraction analyses suggested that Ni and Cu atoms form a homogeneous solid solution in the Ni-Cu nanoporous architecture. The ligament sizes of nanoporous Ni and Ni-Cu were smaller than that of nanoporous Cu, reflecting the difference between diffusivities of Ni and Cu at solid/electrolyte interface. Ni can reduce the pore and ligament sizes of resulting nanoporous architecture when added to initial Cu-Mn alloys.

“In-Situ Network” Composite Fibers of Pbzt/Nylon

1988 ◽  
Vol 134 ◽  
Author(s):  
C. Robin Hwang ◽  
Michael F. Malone ◽  
Richard J. Farris ◽  
David C. Martin ◽  
Edwin L. Thomas
Keyword(s):  
Nitrogen Adsorption ◽  
Composite Fibers ◽  
Electron Microscopies ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Before And After ◽  
The Matrix ◽  
Novel Method ◽  
20 Nm

ABSTRACTA novel method of preparing PBZT/nylon composite fibers by infiltrating nylon into pure PBZT fiber is described. The pure PBZT fiber formed a microfibrillar network structure during coagulation, which is effective in reinforcing the matrix in the “in-situ network” composite fibers (designated IC). These new composite fibers exhibit nearly indistinguishable mechanical properties as those of “molecular” composite fibers (MC) prepared from isotropic solutions before and after tension heat-treatment (E = 44 GPa, σ = 430 MPa, ε = 1.2 %, σc = 250 MPa, G = 1.75 GPa) for PBZT/nylon weight ratios equal to unity.The fine structure of pure PBZT and its composite fibers spun from isotropic solutions was characterized using techniques based on nitrogen adsorption, small-angle X-ray scattering, scanning and transmission electron microscopies. The structure of both type of composites was found to be a microfibrillar network of PBZT in a matrix of amorphous nylon. The average diameters of the PBZT microfibrils were in the range of 10 to 20 nm for the IC and 4 nm for the MC.

Microstructural and basic mechanical characteristics of ZA27 alloy-based nanocomposites synthesized by mechanical milling and compocasting

2018 ◽  
Vol 53 (15) ◽  
pp. 2033-2046 ◽  
Author(s):  
Biljana Bobić ◽  
Aleksandar Vencl ◽  
Jovana Ružić ◽  
Ilija Bobić ◽  
Zvonko Damnjanović
Keyword(s):  
Yield Strength ◽  
Mechanical Milling ◽  
Metal Matrix ◽  
Matrix Alloy ◽  
Compressive Yield Strength ◽  
Za27 Alloy ◽  
The Matrix ◽  
The Difference ◽  
Ball Milling Technique ◽  
Semi Solid

Particulate nanocomposites with the base of ZA27 alloy were synthesized using an innovative route, which includes mechanical milling and compocasting. Scrap from the matrix alloy and ceramic nanoreinforcements were mechanically milled using the ball-milling technique, which led to the formation of composite microparticles. The use of these particles in the compocasting process provided better wettability of ceramic nanoreinforcements in the semi-solid metal matrix, which resulted in a relatively good dispersion of the nanoreinforcements in nanocomposite castings. The presence of nanoreinforcements led to the grain refinement in the matrix of nanocomposites. The mechanical properties of the synthesized nanocomposites are improved and compared with the properties of the metal matrix. The observed increase in the hardness of nanocomposites with Al2O3 nanoreinforcements (20–30 nm) was 6.5% to 10.8%, while the yield strength of these nanocomposites has increased by 12.2% to 23.2%. The hardness and compressive yield strength of the nanocomposites with Al2O3 nanoparticles (100 nm) increased by 1.7% to 8.0% and 2.3% to 8.3%, respectively. The increase in hardness of the nanocomposites with SiC nanoparticles (50 nm) was 11.5% to 20.6%, while the increase in the yield strength was 15.6% to 24.5%. The greatest contribution to the overall strengthening in the synthesized nanocomposites is the result of increased dislocation density due to the difference in coefficients of thermal expansion for the matrix alloy and nanoreinforcements.

EFFECT OF SUBSTRATE THICKNESS ON NANOSTRUCTURE AND MECHANICAL PROPERTIES OF BULK NANOCRYSTALLINE Fe3Al PREPARED BY ALUMINOTHERMIC REACTION

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1572-1577
Author(s):  
PEIQING LA ◽  
LI WANG ◽  
YANG ZHAO ◽  
CHUNJIE CHEN
Keyword(s):  
Grain Size ◽  
Nanocrystalline Phase ◽  
Substrate Thickness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminothermic Reaction ◽  
Transmission Electron ◽  
Bulk Nanocrystalline ◽  
Nanocrystalline Phases ◽  
Different Thickness

Bulk nanocrystalline Fe 3 Al materials were prepared by aluminothermic reaction on the substrates with different thickness of 5~15 mm . Grain size of the materials was measured by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Compressive strength and hardness of the materials were tested. The results showed the materials consisted of amorphous and nanocrystalline phases. With the substrate thickness increasing, amount of the nanocrystalline phase increased and that of the amorphous decreased and grain size of the nanocrystalline increased and a few grains in micrometer appeared in part areas of the materials. Yield strength and hardness of the materials remarkably decreased with the substrate thickness.

Blends containing core-shell impact modifiers Part 1. Structure and tensile deformation mechanisms (IUPAC Technical Report)

2001 ◽  
Vol 73 (6) ◽  
pp. 897-912 ◽  
Author(s):  
C. B. Bucknall
Keyword(s):  
Tensile Deformation ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Glass Transitions ◽  
Volume Increase ◽  
Transmission Electron ◽  
Technical Report ◽  
The Matrix ◽  
20 Nm

Two impact modifiers, based respectively on polybutadiene (PB) and poly(butyl acrylate-co-styrene) (PBA), are compared in blends with four glassy polymers: polycarbonate (PC), poly(methyl methacrylate) (PMMA), poly(styrene-co-acrylonitrile) (PSAN), and poly(vinyl chloride) (PVC). Dynamic mechanical tests show glass transitions at about -80 °C in PB and -15 °C in PBA. Both modifiers have grafted PMMA shells, which are seen in the transmission electron microscope (TEM) to be about 10 nm thick. The two-stage PB particles have 200-nm-diameter polybutadiene cores, whereas the three-stage PBA particles have 260-nm-diameter PMMA cores, with 20-nm thick PBA rubber inner shells. Under tension, the PB particles cavitate to form single voids on reaching a critical volume strain, and subsequently offer little resistance to dilatation. By contrast, tensile tests performed in situ in the TEM show that the PBA shells form fibrils that are anchored to the rigid core, and act as constraints on further dilatation: the stresses developed in the PBA fibrils can be sufficient to draw fibrils from both the PMMA core and the PSAN matrix. There is evidence that the PMMA shells can debond from the matrix both in cryogenic fracture and in fatigue at 23 °C. Tensile dilatometry shows that the PB particles cavitate at higher strains than the PBA particles, but that the PB particles then cause a rapid volume increase, leading to a low strain at break. By contrast, the PBA particles produce a more controlled dilatation, and higher strains to break. Later papers in this series treat the mechanical and rheological behavior of these blends in more detail.

Preparation and Mechanical Properties of Ultrafine Grained Metals

1990 ◽  
Vol 195 ◽  
Author(s):  
B. Gunther ◽  
A. Baalmann ◽  
H. Weiss
Keyword(s):  
Yield Strength ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Strengthening Effect ◽  
Ultrafine Grained ◽  
Concurrent Processes ◽  
Evaporation Technique ◽  
Cold Worked ◽  
20 Nm ◽  
Coble Creep

ABSTRACTUltrafine—grained polycrystalline metallic components (Cu, Au, Fe) have been prepared by means of the inert gas evaporation technique combined with an integrated uniaxial cold compaction device. The average grain sizes ranaed typically from 20 nm to about 100 nm. The microstructure and Imourity content of the as-pressed samples have been investigated by means of TEM and AES, respectively. The yield strength of ultrafine (30 nm) grained Cu specimens obtained in tensile tests compares well with respective values for heavily cold—worked coarse grained copper. Al slight heat treatment (150ºC/30min) improves the strain—to—fracture at slightly reduced yield strength values. The results are discussed within the picture of two concurrent processes determining the strength of ultrafine grained metals: Coble creep vs. grain boundary strengthening effect.

Microstructure and Creep Properties of Silicon- and/or Germanium-Bearing Near-α Titanium Alloys

2016 ◽  
Vol 879 ◽  
pp. 2324-2329 ◽  
Author(s):  
Tomonrori Kitashima ◽  
K.S. Suresh ◽  
T. Hara ◽  
Yoko Yamabe-Mitarai ◽  
Y. Toda
Keyword(s):  
Solid Solution ◽  
High Resolution ◽  
Strain Rate ◽  
Creep Strain ◽  
Creep Strain Rate ◽  
Alloying Effect ◽  
Creep Properties ◽  
Transmission Electron ◽  
The Matrix ◽  
Fringe Patterns

The effects of Si and/or Ge addition on the microstructure and creep properties at 650°C and 137 MPa were investigated in near-α Ti–Al–Sn–Zr–Mo alloys. Si and/or Ge addition decreased the minimum creep strain rate owing to the solid solution of Si and Ge in the matrix and the precipitation of silicide, germanide, and their solid solutions. The decrease in the minimum creep strain rate in the alloy with 1 wt% Ge without Si was the most significant because of the formation of very fine germanide precipitates. In addition, a marked shift in the lattice parameters of the α and β phases was detected for the alloy with 4 wt% Ge. The Moiré fringe patterns at the α/β interfaces in the alloys were investigated using high-resolution transmission electron micrographs to discuss the alloying effect on the structure of the interfaces.

Ti (CN) Precipitation in Ultra-High Strength Ti Micro-Alloyed Steels with 700MPa Yield Strength on TSCR Process

2013 ◽  
Vol 842 ◽  
pp. 61-69 ◽  
Author(s):  
Qi Lin Chen ◽  
Xin Ping Mao ◽  
Xin Jun Sun
Keyword(s):  
Yield Strength ◽  
Volume Fraction ◽  
High Strength ◽  
High Volume ◽  
Thermal Simulation ◽  
Cast Slab ◽  
Transmission Electron ◽  
The Matrix ◽  
Segregation Band ◽  
Physical And Chemical

Precipitates in ultra-high strength Ti micro-alloyed strips with 700MPa yield strength on TSCR process and in the thermal simulation experimental specimen are observed via Scanning Electronic Microscope (SEM) and Transmission Electron Microscope (TEM), the results show that: the precipitates in the Ti micro-alloyed cast slab thermal simulation experiment can be divided into three categories: 1) micron-sized liquation TiN, 2) 100-200nm sized TiC formed along original austenite grain boundaries or along the dendrite segregation band, 3) solid precipitated 50-100nm sized TiN. Deformation induced spherical TiC (about 10nm-30nm) homogeneously distributed in the matrix after the austenite deformation .After simulated coiling, dispersed TiC (about 5-15nm ) precipitated from ferrite are found in the specimen. TiN with hundreds of nanometers size are commonly found in Ti micro-alloyed strips in industrial production. Ti4C2S2and Ti (CN) are complex precipitated, Ti4C2S2size is less than 30nm; physical and chemical phase analysis shows that the nanosized TiC precipitates are characterized by high volume fraction and small dimensions.

Sign in / Sign up

Export Citation Format

Share Document