SANS Study of Carbon Addition in Ti–45Al–5Nb

2011 ◽  
Vol 1295 ◽  
Author(s):  
P. Staron ◽  
F.-P. Schimansky ◽  
C. Scheu ◽  
H. Clemens
Keyword(s):  
Neutron Scattering ◽  
Size Distribution ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Tial Alloy ◽  
Small Volume ◽  
Volume Fraction ◽  
Atom Probe ◽  
Carbon Addition ◽  
Small Volume Fraction

ABSTRACTThe distribution of carbon in Ti–45Al–5Nb–0.5C was studied using small-angle neutron scattering (SANS). In an earlier study, carbon had been found to form small perovskite precipitates in a γ-TiAl alloy without Nb, which significantly increase the strength of the material. In the Nb-containing alloy, however, no strengthening precipitates were observed, but most of the C was found to be homogeneously distributed. Atom probe investigations revealed only few C-enriched regions. The present SANS investigation was carried out to confirm the presence and size distribution of these C-enriched regions in the material. The SANS results show that a small volume fraction of such C-enriched regions is present, while the large number of small precipitates found in the alloy without Nb is indeed missing in the Nb-containing alloy.

scholarly journals Critical Consideration of Precipitate Analysis of Fe–1 at.% Cu Using Atom Probe and Small-Angle Neutron Scattering

2010 ◽  
Vol 17 (1) ◽  
pp. 26-33 ◽  
Author(s):  
M. Schober ◽  
E. Eidenberger ◽  
P. Staron ◽  
H. Leitner
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Search Algorithm ◽  
Atom Probe ◽  
Magnetic Scattering ◽  
Model Alloy ◽  
Chemical Compositions ◽  
Heat Treated

AbstractAn Fe–1 at.% Cu model alloy was examined by atom probe (3DAP) and small-angle neutron scattering (SANS) to verify the accordance of the gained results. The Fe-Cu alloy was heat-treated for various times at 500°C, forming Cu-rich precipitates within the Fe matrix. The chemical compositions of the precipitates and matrix found by 3DAP were used to calculate the magnetic scattering contrast. Additionally, a magnetic moment of the precipitates that contain a significant amount of Fe was taken into account for the calculation of magnetic scattering contrast. This in turn is used for the evaluation of the magnetic scattering curves gained by SANS. Both the 3DAP data as well as the scattering curves were analyzed with regard to radius, number density, and volume fraction of the precipitates as a function of aging time. The results yielded by both techniques are in good agreement and correspond to the development of the hardness of the alloy. Minor differences can be related to the cluster search algorithm used for the analysis of the 3DAP data as well as Fe overestimation based on different field phases.

Characterization of alumina powder using multiple small-angle neutron scattering. I. Theory

1985 ◽  
Vol 18 (6) ◽  
pp. 467-472 ◽  
Author(s):  
N. F. Berk ◽  
K. A. Hardman-Rhyne
Keyword(s):  
Particle Size ◽  
Phase Shift ◽  
Neutron Scattering ◽  
Multiple Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Scattering Data ◽  
Alumina Powder ◽  
Beam Broadening

Microstructural parameters of high-purity alumina powder are determined quantitatively throughout the bulk of the material using small-angle neutron scattering techniques. A unified theoretical and experimental approach for analyzing multiple scattering data is developed to obtain values for particle size, volume fraction and surface area. It is shown how particle size and volume fraction can be measured in a practical way from SANS data totally dominated by incoherent multiple scattering (`beam broadening'). The general phase-shift dependence of single-particle scattering is incorporated into the multiple scattering formalism, and it is also shown that the diffractive limit (small phase shift) applies even for phase shifts as large as unity (particle radii of order 1 μm). The stability of the Porod law against multiple scattering and the phase-shift scale are described, a useful empirical formula for analysis of beam broadening data is exhibited, and the applicability of the formulations to polydispersed systems is discussed.

Determination of γ′ solution temperature in Re-rich Ni-base superalloy by small-angle neutron scattering

2001 ◽  
Vol 34 (5) ◽  
pp. 541-548 ◽  
Author(s):  
Pavel Strunz ◽  
Debashis Mukherji ◽  
Ralph Gilles ◽  
Albrecht Wiedenmann ◽  
Hartmut Fuess
Keyword(s):  
Neutron Scattering ◽  
Temperature Dependence ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Solidus Temperature ◽  
Solution Temperature ◽  
Incipient Melting ◽  
Relative Volume Fraction

A harmful segregation of heavy elements (e.g.W, Mo, Re) during solidification of Ni-base superalloys can only be eliminated by using a homogenizing heat treatment, which needs to be carried out in the single-phase (γ) field above the γ′ solvus temperature but below the solidus temperature. Small-angle neutron scattering (SANS) was employed forin situobservation of the dissolution of precipitates in an Re-rich superalloy. The temperature dependence of the relative volume fraction and the size distribution of smaller γ′ precipitates, and the specific surface of large inhomogeneities as well as some other parameters were determined from the two-dimensional scattering curves measured for as-cast and heat-treated samples. Overlap of the incipient melting region with the region where a certain amount of precipitates remained undissolved was observed, thus complicating a determination of the temperature at which all γ′ precipitates are already dissolved. Nevertheless, conclusions about the temperature at which the precipitates dissolve and about the temperature at which the incipient melting starts could be formulated. The total scattering probability is suggested as the measure of the overall homogeneity of the distribution of elements in the sample. The temperature dependence of this parameter indicates the optimum solution procedure.

scholarly journals VC-Precipitation Kinetics Studied by Small-Angle Neutron Scattering in Nano-Steels

2018 ◽  
Vol 941 ◽  
pp. 236-244 ◽  
Author(s):  
Chrysoula Ioannidou ◽  
Zaloa Arechabaleta ◽  
Arjan Rijkenberg ◽  
Robert M. Dalgliesh ◽  
A.A. van Well ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Neutron Scattering ◽  
Small Angle ◽  
Inductively Coupled Plasma ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Optical Emission ◽  
Scattering Data ◽  
High Tech ◽  
Precipitation Kinetics

Nanosteels are used in automotive applications to accomplish resource-efficiency while providing high-tech properties. Quantitative data and further understanding on the precipitation kinetics in Nanosteels can contribute to fulfil this goal. Small-Angle Neutron Scattering measurements are performed on a Fe-C-Mn-V steel, previously heat-treated in a dilatometer at 650°C for several holding times from seconds to 10 hours. The evolution of the precipitate volume fraction, size distribution and number density is calculated by fitting the experimental Small-Angle Neutron Scattering curves. The effect of phase transformation on precipitation kinetics is also discussed. Complementary Transmission Electron Microscopy, Scanning Electron Microscopy and Inductively Coupled Plasma Optical Emission Spectroscopy measurements are performed to support the Small-Angle Neutron Scattering data analysis.

scholarly journals An integrated pore size distribution measurement method of small angle neutron scattering and mercury intrusion capillary pressure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rui Shen ◽  
Xiaoyi Zhang ◽  
Yubin Ke ◽  
Wei Xiong ◽  
Hekun Guo ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Capillary Pressure ◽  
Size Distribution ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Measurement Method ◽  
Full Scale ◽  
Mercury Intrusion

AbstractSmall-angle neutron scattering and high-pressure mercury intrusion capillary pressure testing are integrated to analyze the pore size distribution of the broad sense shale oil reservoir samples of the Permian Lucaogou Formation in the Jimsar Sag, Junggar Basin, China. The results show that, compared with the measurement method integrating gas adsorption and mercury intrusion, combination of small-angle neutron scattering and mercury intrusion can more accurately characterize full-scale pore size distribution. The full-scale pore size distribution curve of the rock samples in the study area includes two types: the declining type and submicron pore-dominated type. The declining type is mainly found with silty mudstone and dolomitic mudstone, and most of its pores are smaller than 80 nm. Silt-fine sandstones and dolarenite are mostly of the submicron pores-dominated type, with most pores smaller than 500 nm. They also present large specific pore volumes and average pore diameters of macropores and are the favorable lithogenous facies for development of high-quality reservoirs.

A small-angle neutron scattering study of fine-scale NbC precipitation kinetics in the α-Fe–Nb–C system

2006 ◽  
Vol 39 (4) ◽  
pp. 473-482 ◽  
Author(s):  
F. Perrard ◽  
A. Deschamps ◽  
F. Bley ◽  
P. Donnadieu ◽  
P. Maugis
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Volume Fraction ◽  
Fine Scale ◽  
Precipitation Kinetics ◽  
Maximum Reaction Rate ◽  
Maximum Reaction ◽  
Neutron Scattering Study ◽  
Precipitate Nucleation

The fine-scale precipitation of NbC in ferrite has been quantitatively characterized in the temperature range 873–1073 K for two alloy compositions, containing respectively 800 p.p.m. Nb and 400 p.p.m. Nb (by weight). Transmission electron microscopy (TEM) has revealed that the precipitates are located on dislocations, and have a plate-like morphology with an average aspect ratio between 2 and 3. Small-angle neutron scattering (SANS) has been systematically used to determine the precipitation kinetics. The validity of the quantitative SANS measurements of size and volume fraction has been assessed by TEM image analysis and chemical dissolution experiments. The precipitation kinetics is observed to depend strongly on temperature but to be similar for the two alloy compositions. From the measurements, it is inferred that precipitate nucleation is extremely rapid, in relation to the nature of the nucleation sites. A time–temperature transformation diagram is built from the kinetic data, showing a maximum reaction rate between 973 and 1073 K.

Revisiting Temporal Evolution of Cu-Rich Precipitates in Fe–Cu Alloy: Correlative Small Angle Neutron Scattering and Atom-Probe Tomography Studies

2019 ◽  
Vol 25 (4) ◽  
pp. 840-848 ◽  
Author(s):  
Sarita Ahlawat ◽  
Sudip Kumar Sarkar ◽  
Debasis Sen ◽  
Aniruddha Biswas
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Atom Probe Tomography ◽  
Small Angle Neutron Scattering ◽  
Nuclear Reactor ◽  
Temporal Evolution ◽  
Morphological Evolution ◽  
Atom Probe ◽  
Pressure Vessels ◽  
Morphological Transformation

AbstractBinary Fe–Cu alloys are effective prototypes for investigating radiation-induced formation and growth of nanometric Cu-rich precipitates (CRPs) in nuclear reactor pressure vessels. In this report, the temporal evolution of CRPs during thermal aging of Fe–Cu binary alloys has been investigated by using complementary techniques such as atom probe tomography (APT) and small-angle neutron scattering (SANS). We report a detailed quantitative evolution of a rarely observed morphological transformation of Cu precipitates from spherical to ellipsoid with a significant change (approximately two times) in aspect ratio, an effect known to be associated with the 9R-3R structural transition of the precipitates. It is demonstrated through APT that the precipitates remain spherical up to 8 h, however, they subsequently convert to oblate ellipsoid upon further aging. SANS analysis also detected signs of this morphological transition in reciprocal space. Furthermore, SANS quantifies evolution of the precipitates and corroborates well with the APT results. Interestingly, the power-law exponent of the temporal evolution for mean size and number density agree reasonably well with the Lifshitz–Slyozov–Wagner model, in spite of the complex morphological evolution of the precipitates.

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