scholarly journals Automated SEM/EDS Analysis for Assessment of Trace Cross-Contamination in 316L Stainless Steel Powders

2021 ◽  
Author(s):  
MarÍa J. Balart ◽  
Xinjiang Hao ◽  
Claire L. Davis
Keyword(s):  
Cross Sections ◽  
Bulk Sample ◽  
Cross Contamination ◽  
Near Surface ◽  
Root Cause ◽  
Eds Analysis ◽  
Detection And Identification ◽  
Powder Samples ◽  
316L Steel ◽  
Local Enrichment

AbstractFollowing observations of microcracking in two, out of three, Additive manufactured (AM) 316L steel samples, an investigation was undertaken to ascertain the root cause. Welding diagrams, taking into account composition and process parameters, could not generally account for the experimental observations of non-cracked versus cracked AM 316L samples. EBSD phase maps in all three AM samples exhibited a fully austenitic microstructure not only in the bulk sample but also near-surface. Analysis of microcracked regions in the AM samples showed the presence of local enrichment of Ni, Cu and P. Automated SEM/EDS analysis on feedstock powder samples prepared for cross-section examination revealed a fine, foreign particulate contaminant, expected to arise from NiCrCuP alloy cross-contamination during atomization, to be completely embedded in a 316L powder particle. This type of contamination would not have been revealed on examination of powder mounted onto a SEM stub, a common approach to assess powder quality. Based on this analysis, it is recommended to consider including automated SEM/EDS analysis on powder cross-sections in any standardization protocol for quality control of powders, to increase the chances of detection and identification of fine cross-contaminants. It is also recommended that atomization of NiCrCuP alloy should no longer precede atomization of 316L alloy.

scholarly journals Evaluation of Forecasts of a Convectively Generated Bore Using an Intensively Observed Case Study from PECAN

2018 ◽  
Vol 146 (9) ◽  
pp. 3097-3122 ◽  
Author(s):  
Aaron Johnson ◽  
Xuguang Wang ◽  
Kevin R. Haghi ◽  
David B. Parsons
Keyword(s):  
Cross Sections ◽  
Turbulent Mixing ◽  
Weather Research And Forecasting ◽  
Cold Pool ◽  
Model Errors ◽  
Near Surface ◽  
Cold Pools ◽  
Convection Model

Abstract This paper presents a case study from an intensive observing period (IOP) during the Plains Elevated Convection at Night (PECAN) field experiment that was focused on a bore generated by nocturnal convection. Observations from PECAN IOP 25 on 11 July 2015 are used to evaluate the performance of high-resolution Weather Research and Forecasting Model forecasts, initialized using the Gridpoint Statistical Interpolation (GSI)-based ensemble Kalman filter. The focus is on understanding model errors and sensitivities in order to guide forecast improvements for bores associated with nocturnal convection. Model simulations of the bore amplitude are compared against eight retrieved vertical cross sections through the bore during the IOP. Sensitivities of forecasts to microphysics and planetary boundary layer (PBL) parameterizations are also investigated. Forecasts initialized before the bore pulls away from the convection show a more realistic bore than forecasts initialized later from analyses of the bore itself, in part due to the smoothing of the existing bore in the ensemble mean. Experiments show that the different microphysics schemes impact the quality of the simulations with unrealistically weak cold pools and bores with the Thompson and Morrison microphysics schemes, cold pools too strong with the WDM6 and more accurate with the WSM6 schemes. Most PBL schemes produced a realistic bore response to the cold pool, with the exception of the Mellor–Yamada–Nakanishi–Niino (MYNN) scheme, which creates too much turbulent mixing atop the bore. A new method of objectively estimating the depth of the near-surface stable layer corresponding to a simple two-layer model is also introduced, and the impacts of turbulent mixing on this estimate are discussed.

Focused Ion Beam Metrology

1995 ◽  
Vol 396 ◽  
Author(s):  
A. Wagner ◽  
P. Blauner ◽  
P. Longo ◽  
S. Cohen
Keyword(s):  
Integrated Circuits ◽  
Cross Sections ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Dimensional Change ◽  
Critical Dimension ◽  
Ion Beams ◽  
Near Surface ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes

AbstractFocused Ion Beams offer a new method of measuring the size of polymer resist features on integrated circuits. The short penetration range of an ion relative to an electron is shown to offer fundamental advantages for critical dimension (CD) metrology. By confining the polymer damage to the very near surface, ion beams can induce less dimensional change than scanning electron microscopes during the measurement process. This can result in improved CD measurement precision. The erosion rate of polymers to various ion species is also presented, and we show that erosion is non-linear with ion dose. The use of FIB for forming resist cross sections is also demonstrated. An H20 gas assisted etching process for polymers has been developed, and is shown to significantly improve the quality of resist cross sections.

Spin-Dependence of the Electron Scattering Cross Section by a Magnetic Layer System and the Magneto-Resistance

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3376-3380 ◽  
Author(s):  
J. T. Wang ◽  
F. Tang ◽  
W. D. Brown ◽  
D. Bagayoko
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Magnetic Layer ◽  
Bulk Sample ◽  
Scattering Cross Section ◽  
Layer System ◽  
Interfacial Roughness ◽  
Scattering Cross ◽  
Experimental Findings ◽  
Magneto Resistance

We present a theoretical model for calculating the spin-dependent cross section of the scattering of electrons by a magnetic layer system. Our model demonstrates that the cross sections of the scattering are different for spin up and spin down electrons. The model assumes that the electrical resistivity in a conductor is proportional to the scattering cross section of the electron in it. It is believed to support the two channel mechanism in interpreting magneto-resistance (MR). Based on the model without considering the scattering due to the interfacial roughness and the spin flipping scattering, we have established a relationship between MR and the square of the magnetic moment in the bulk sample without considering the scattering due to the interfacial roughness and the spin flipping scattering. It can also qualitatively explain the MR difference between the current in plane (CIP) and current perpendicular to the plane (CPP) configurations. The predictions by the model agree well with the experimental findings.

scholarly journals A Detailed Study of the 12C(d,p0)13C Reaction at Detector Angles between 135 ° and 170 °, for the Energy Range Ed,lab = 900-2000 keV

2019 ◽  
Vol 14 ◽  
pp. 95
Author(s):  
M. Kokkoris ◽  
P. Misaelides ◽  
S. Kossionides ◽  
Ch. Zarkadas ◽  
A. Lagoyannis ◽  
...  
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Depth Distribution ◽  
Projectile Energy ◽  
Published Data ◽  
Surface Layers ◽  
Near Surface ◽  
Nominal Thickness ◽  
Natural Carbon

The differential cross sections of the 12C(d,po)13C reaction applied to the determination of the depth distribution of carbon in near-surface layers of materials were determined in the projectile energy region F,dtiab — 900-2000 keV (in steps of 25 keV) and for detector angles between 135 ° and 170 ° (in steps of 5 ° ) using as targets 99.9% purity self-supported natural carbon (98.9% 12C - 1.1% 13C) foils of nominal thickness ca. lxlO18 at/cm2. The overall error in the absolute differential cross section measurements varied between ~6-22%. The results were compared with already published data and the explanation of the occurring differences was attempted.

scholarly journals EFFECT OF FRICTION ON THE MICROMECHANICAL PROPERTIES OF AISI 316L AUSTENITIC STEEL

2021 ◽  
Vol XXVIII (2) ◽  
pp. 34-43
Author(s):  
Daria Grabco ◽  
◽  
Constantin Pyrtsac ◽  
Daria Topal ◽  
Olga Shikimaka ◽  
...  
Keyword(s):  
Austenitic Steel ◽  
Resistance Index ◽  
Steel Structure ◽  
Aisi 316L ◽  
Near Surface ◽  
Fine Grained ◽  
316L Steel ◽  
Micromechanical Characteristics ◽  
Friction Method ◽  
Potential Use

In this paper, we investigate the possibility of using the friction method for modifying the microstructure and mechanical properties in the near-surface regions of AISI 316L austenitic steel specimens for the purpose of its practical application. It is shown that a region of severe plastic deformation arises near the friction surface, which transforms the initial fine-grained polycrystalline steel structure into a homogenized zone consisting of a deformed structure with plastic slip bands and weakly pronounced grain boundaries. The change in the microscopic structure results in an increase in this zone of values of micromechanical characteristics, such as microhardness (H), Young's modulus (E), plasticity index (H/E) and resistance index (H3/E2). The obtained results are of interest for the potential use of AISI 316L steel in medicine.

scholarly journals Reviving Alexander Calder’s Man-Eater with Pennants: A Technical Examination of the Original Paint Palette

Heritage ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 1920-1937
Author(s):  
Abed Haddad ◽  
Megan Randall ◽  
Lynda Zycherman ◽  
Ana Martins
Keyword(s):  
Cross Sections ◽  
Modern Art ◽  
Museum Of Modern Art ◽  
Eds Analysis ◽  
Technical Examination ◽  
Red Lead ◽  
Early Primary ◽  
Titanium White ◽  
The Many ◽  
Color Scheme

Mat-Eater with Pennants, a rarely exhibited sculpture in Alexander Calder’s oeuvre, was commissioned by The Museum of Modern Art (MoMA) and installed in 1945. To exhibit the large standing mobile in Alexander Calder: Modern from the Start (2021), the derelict sculpture had to be remediated; this initiated a collaborative investigation with conservation scientists, conservators, curators, and the Calder Foundation into the original paint colors hidden beneath layers of repaint. XRF analysis was carried out to elucidate the paints’ composition, followed by sampling for analysis to assess the paint stratigraphy and binders. Scrapings were analyzed by µ-FTIR and Raman spectroscopies; cross sections were examined with optical microscopy and analyzed with SEM-EDS. Analysis differentiated between the original paints, which contain Prussian blue, parachlor red, chrome yellow, and the many layers of overpaint, which contain titanium white, molybdate orange, a variety of β-Naphthol reds, red lead, and ultramarine. A model for Man-Eater, Mobile with 14 Flags, is also part of the museum’s collection, and was first considered as a point of reference for the original colors. Similar analysis, however, indicates that the maquette was painted after the Man-Eater was first installed, therefore is not representative of the original colors. In addition to investigating an early primary palette for Calder’s outdoor sculptures, this study helped develop the plan for the restoration of the original color scheme of Man-Eater.

Using High Speed Camera Metrology in Support of Failure Analysis and Product Development

2005 ◽  
Author(s):  
Wade Hezeltine ◽  
Richard L. Williams ◽  
Frank Z. Liang
Keyword(s):  
Cross Sections ◽  
High Speed ◽  
Development Time ◽  
High Speed Camera ◽  
High Speed Imaging ◽  
Cycle Times ◽  
Root Cause ◽  
Dynamic Event ◽  
Design Cycle ◽  
Market Opportunities

Abstract Typical failure analyses metrologies for dynamic failures are cross-sections, microscopy, dye-and-pull, optical and SEM. Using these traditional metrologies to find root cause for a dynamic event can be very time consuming and often the results cannot point directly to the root cause itself. The standard approach is to work backward to reconstruct the “event” that caused or initiated the failure. Often the root cause is not immediately obvious and iterative testing to identify the true root cause is costly in time, materials and resources. At Intel we have been using high speed imaging and motion analysis (HSIMA) to identify the failure at the point of initiation. Using the point of initiation concept with reconstructive modeling allows a design team to identify potential initiating sources and better match and implement corrective action. HSIMS has proven to decreases development time, minimized product design cycle and increases market opportunities by decreasing cycle times to root cause of failures.

A Prognostics Approach Connecting Oxidation Damage to Mechanical Criteria

2020 ◽  
Author(s):  
Pontus Slottner
Keyword(s):  
Oxidation State ◽  
Cross Sections ◽  
Gas Turbines ◽  
Time Integration ◽  
Cross Sectional ◽  
Performance Loss ◽  
Mathematical Algorithm ◽  
Root Cause ◽  
Oxidation Damage ◽  
And Performance

Abstract Oxidation of gas turbine parts is one of the damage mechanisms limiting firing rate and outage interval, thereby reducing potential efficiency and increasing operational cost. While oxidation isn’t an immediate integrity threat in itself, it has indirect impact by reducing load carrying cross sections, changing weight and stiffness distribution, causing cooling air leakages, changing material properties, changing parts aerodynamics characteristics et cetera. This in turn potentially results in shorter creep life, drifting eigenfrequencies, overheating of other parts, increased brittleness and performance loss. Since it is very complicated to analyze all these possible situations in detail, parts are often rejected because of their appearance rather than because of actually approaching a level of damage where it will have consequences on the operability of the turbine. Further, the rules tend to be general rather than customer specific, being set for the entire allowed operation envelope of the part rather than based upon the particular conditions of the unit where the part is in service. This paper presents a simple, first-step prognostics model that connects oxidation damage to local one-dimensional stress and stiffness and local cross-sectional force. An example is given where simple oxidation models are used to predict a detailed oxidation state with regard to multiple aspects. Herein, this oxidation state includes different aspects with regard to the type of oxidation and includes additional characteristics to be considered in the following. By connecting the model to measured characteristics instead of pure oxidation criteria it will be easier to: firstly, apply more relevant criteria that can be evaluated on a site-by-site basis. This will allow high-precision oxidation prognostics with criteria relevant for the operational safety of the equipment. Secondly, more accurately compare predictions to experiences, allowing more detailed operation experience evaluation as well as more relevant input to root cause investigations. This will allow more accurate root cause determination and will result in fewer data points needed to draw statistically sound conclusions from field experiences. Providing such possibility has a significant impact on corresponding applications, as it includes larger operation. Simultaneously, risks can be controlled and quantified better than today providing an important benefit for an application like gas turbines depending strongly on the reliability of the components utilized. The model is general in its nature and is formulated to allow application with any oxidation rule that can be formulated as a mathematical algorithm that is suitable for time integration. The main limitations are its restriction to one space dimension and the assumption of a constant temperature field. If the model is found useful, natural next steps are to extend the model to three space dimensions and a more complex temperature model. The model should also be tested with more accurate oxidation models.

scholarly journals Near-Surface Geochemical Anomalies Integrated with Seismic and Well Data over the Contact of the Outer Carpathians and the Carpathian Foredeep (SE Poland)

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Henryk Sechman ◽  
Adrianna Góra ◽  
Anna Twaróg ◽  
Piotr Guzy ◽  
Ewelina Górska-Mruk ◽  
...  
Keyword(s):  
Cross Sections ◽  
Soil Gas ◽  
High Positive Correlation ◽  
Near Surface ◽  
Geochemical Anomalies ◽  
Se Poland ◽  
Fold And Thrust Belt ◽  
Carpathian Foredeep ◽  
Outer Carpathians ◽  
Well Data

The objective of this study is to interpret the regularities in distribution of surface geochemical anomalies observed in a fragment of the contact zone between the Carpathian Fold-and-Thrust Belt and the Carpathian Foredeep (SE Poland). The surface geochemical survey included a total of 670 soil gas samples analyzed by gas chromatography, integrated with seismic cross sections, and supplemented by production data from wells. Maximum concentrations of methane, total alkanes C2-C5, total alkenes C2-C4, H2, and CO2measured in soil gas samples were 27.1 vol.%, 45.3 ppm, 0.49 ppm, 0.232 vol.%, and 6.29 vol.%, respectively. Traces of alkanes detected in samples are the result of microseepage from a few accumulations of various compositions. Methane and ethane migrate primarily from relative shallow Miocene strata, and higher alkanes from deeper Miocene strata and from Paleozoic-Mesozoic basement. We found relatively high positive correlation between the distribution of surface geochemical anomalies and the relative intensity of hydrocarbon shows recorded in the wells. The location and range of 13 anomalous zones are controlled by the patterns of both the Dębno and the Wojnicz slice-folds. Most of the anomalies occur over the Wojnicz Trough, suggesting the presence of conventional accumulations and/or the sites where the Miocene mudstone and heterolithic formations are saturated with gas.

Premature Cracking of Dies for Aluminium Alloy Die-Casting

2013 ◽  
Vol 58 (4) ◽  
pp. 1275-1279 ◽  
Author(s):  
B. Pawłowski ◽  
P. Bala ◽  
T. Tokarski ◽  
J. Krawczyk
Keyword(s):  
Heat Treatment ◽  
Aluminium Alloy ◽  
Die Casting ◽  
Metallographic Examination ◽  
Root Cause ◽  
Parallel Cracks ◽  
Eds Analysis ◽  
Working Surface ◽  
Quenching And Tempering ◽  
Mechanical Nature

Abstract Two identical dies for aluminium alloy die-casting failed prematurely because of a number of parallel cracks on the working surface. These cracks were of a mechanical nature related to incorrect microstructural banding orientation of the die core and related to improper heat treatment. The microstructural banding orientation was determined by metallographic examination of the specimens, which were cut from the dies along the three axes of the coordinate system. Scanning electron microscopy (SEM) examination of the fracture surfaces and along the crack path (including energy dispersive spectroscopy (EDS) analysis) indicated that the root cause of the premature cracking of the dies was improper heat treatment (quenching and tempering conditions). Additionally, resistance to fracture of the investigated specimens, as measured by the Charpy V-notch test, was five times lower than that required for the desired hardness.

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