scholarly journals Multiscale Characterization of An Oxide Scale Formed on the Creep-Resistant ATI 718Plus Superalloy during High-Temperature Oxidation

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6327
Author(s):  
Adam Kruk ◽  
Aleksander Gil ◽  
Sebastian Lech ◽  
Grzegorz Cempura ◽  
Alina Agüero ◽  
...  
Keyword(s):  
Phase Distribution ◽  
3D Visualization ◽  
Three Dimensional ◽  
High Strength ◽  
Temperature Oxidation ◽  
Near Surface ◽  
Cr2o3 Scale ◽  
Surface Areas ◽  
The Difference ◽  
Original Insight

The ATI 718Plus® is a creep-resistant nickel-based superalloy exhibiting high strength and excellent oxidation resistance in high temperatures. The present study is focused on multiscale 2D and 3D characterization (morphological and chemical) of the scale and the layer beneath formed on the ATI 718Plus superalloy during oxidation at 850 °C up to 4000 h in dry and wet air. The oxidized samples were characterized using various microscopic methods (SEM, TEM and STEM), energy-dispersive X-ray spectroscopy and electron diffraction. The 3D visualization of the microstructural features was achieved by means of FIB-SEM tomography. When oxidized in dry air, the ATI 718Plus develops a protective, dense Cr2O3 scale with a dual-layered structure. The outer Cr2O3 layer is composed of coarser grains with a columnar shape, while the inner one features fine, equiaxed grains. The Cr2O3 scale formed in wet air is single-layered and features very fine grains. The article discusses the difference between the structure, chemistry and three-dimensional phase distribution of the oxide scales and near-surface areas developed in the two environments. Electron microscopy/spectroscopy findings combined with the three-dimensional reconstruction of the microstructure provide original insight into the role of the oxidation environment on the structure of the ATI 718Plus at the nanoscale.

scholarly journals The influence of high-temperature oxidation on the phase distribution of metal substrate in duplex stainless steel

2021 ◽  
Author(s):  
Minami Matsumoto ◽  
Ken Kimura ◽  
Natsuko Sugiura
Keyword(s):  
Stainless Steels ◽  
Room Temperature ◽  
Phase Distribution ◽  
High Strength ◽  
Metal Substrate ◽  
Temperature Oxidation ◽  
Good Corrosion Resistance ◽  
Mn Oxide ◽  
Typical Type ◽  
Compositional Changes

AbstractDuplex stainless steels (DSSs), which consist of ferrite and austenite phases, are widely used owing to their high strength and good corrosion resistance. However, the oxidation behavior of DSSs is extremely complicated because they have dual phases. In this study, changes in the scale and the metal substrate during oxidation were investigated. UNS S32101 (Fe-21.5%Cr–5%Mn–1.5%Ni–0.3%Mo–0.22%N), which is a typical type of DSS, was annealed at 1473 K for up to 36 ks in air. The microstructure of UNS S32101 consisted of austenite/ferrite phases, the ratio of which was 50:50 at room temperature. After oxidation, Cr, Mn-oxide formed predominantly. The metal substrate beneath the scale changed mostly to ferrite. In the same region, depletion of Mn and N concentrations resulted. The decrease in Mn was due to the formation of Cr, Mn-oxide. In addition, it was revealed that N content of the metal substrate decreased due to the formation of N2 gas along with the depletion of Mn. It was assumed that the decrease in Mn and N, which are austenite-stabilized elements, led to an increase in ferrite in the depletion area of Mn and N. From this result, it was expected that the compositional changes in the Mn/N depletion area were caused by the oxidation of steel.

Study on overlapping of two sequential scans in laser forming

2007 ◽  
Vol 221 (9) ◽  
pp. 993-997 ◽  
Author(s):  
H Shen ◽  
J Zhou ◽  
Z Q Yao
Keyword(s):  
Plastic Strain ◽  
Material Properties ◽  
Structural Model ◽  
Three Dimensional ◽  
High Strength ◽  
Laser Beams ◽  
Laser Forming ◽  
Numerical Investigations ◽  
Localized Heating ◽  
The Difference

Laser forming can utilize localized heating for the forming of high strength alloys and use combinations of straightandcurved lines to produce three-dimensional formedcomponents, which are of significant value to industries of aerospace, shipbuilding, and microelectronics. A three-dimensional non-linear, indirectly coupled thermal—structural model for the overlapping ratio of two sequential laser beams scanning is established, accounting for temperature dependency of material properties. Numerical results are verified by experimental data. Numerical investigations are carried out to examine the difference in plastic strain distributions under different overlapping ratios. The results show that the bending angle is larger when the size of plastic zone on the top surface is wider, although the plastic strain is smaller.

scholarly journals Three-Dimensional Visualization of Myocardial Ischemia Based on the Standard Twelve-Lead Electrocardiogram

2016 ◽  
Vol 2016 ◽  
pp. 1-8
Author(s):  
Ying Ma ◽  
Yang Sheng ◽  
Tian Ruixia ◽  
Chen Xun
Keyword(s):  
Myocardial Ischemia ◽  
3D Visualization ◽  
Detection Threshold ◽  
Three Dimensional ◽  
Medical Knowledge ◽  
Color Pattern ◽  
Novel Method ◽  
The Difference ◽  
Pseudo Color ◽  
Electrocardiogram Ecg

A novel method was proposed for transforming the ischemic information in the 12-lead electrocardiogram (ECG) into the pseudo-color pattern displayed on a 3D heart model based on the projection of a ST injury vector in this study. The projection of the ST injury vector at a point on the heart surface was used for identifying the presence of myocardial ischemia by the difference between the projection value and the detection threshold. Supposing that myocardial ischemia was uniform and continuous, the location and range of myocardial ischemia could be accurately calculated and visually displayed in a color-encoding way. The diagnoses of the same patient were highly consistent (kappa coefficientk=0.9030) between the proposed method used by ordinary people lacking medical knowledge and the standard 12-lead ECG used by experienced cardiologists. In addition, the diagnostic accuracy of the proposed method was further confirmed by the coronary angiography. The results of this study provide a new way to promote the development of the 3D visualization of the standard 12-lead ECG, which has a great help for inexperienced doctors or ordinary family members in their diagnosis of patients with myocardial ischemia.

scholarly journals Geosphere Coupling and Hydrothermal Anomalies before the 2009 Mw 6.3 L'Aquila Earthquake in Italy

2016 ◽  
Author(s):  
L. X. Wu ◽  
S. Zheng ◽  
A. De Santis ◽  
K. Qin ◽  
R. Di Mauro ◽  
...  
Keyword(s):  
Air Temperature ◽  
3D Visualization ◽  
Three Dimensional ◽  
Surface Air Temperature ◽  
Precipitable Water ◽  
B Value ◽  
Near Surface ◽  
Coupling Process ◽  
Spatio Temporal ◽  
High Level

Abstract. The earthquake (EQ) anomalies associated with the April 6, 2009 Mw 6.3 L'Aquila EQ have been widely reported. Nevertheless, the reported anomalies have not been so far synergically analyzed to interpret or prove the potential LCA coupling process. Previous studies on b-value are also insufficient. In this work, the spatio-temporal evolution of several hydrothermal parameters related to the coversphere and atmosphere, including soil moisture, soil temperature, near-surface air temperature, and precipitable water, was comprehensively investigated. Air temperature and atmospheric aerosol were also statistically analyzed in time series with ground observations. An abnormal enhancement of aerosol occurred on March 30, 2009 and thus proved quasi-synchronous anomalies among the hydrothermal parameters from March 29 to 31 in particular places geo-related to tectonic thrusts and local topography. The three-dimensional (3D) visualization analysis of b-value revealed that regional stress accumulated to a high level, particularly in the L'Aquila basin and around regional large thrusts. Finally, the coupling effects of geospheres were discussed, and a conceptual LCA coupling mode was proposed to interpret the possible mechanisms of the multiple quasi-synchronous anomalies preceding the L’Aquila EQ. Results indicate that CO2-rich fluids in deep crust might have played a significant role in the local LCA coupling process.

scholarly journals Volumetric comparative analysis of anatomy through far-lateral approach: surgical space and exposed tissues

2022 ◽  
Vol 8 (1) ◽  
Author(s):  
Ke Tang ◽  
Xu Feng ◽  
XiaodongYuan ◽  
Yang Li ◽  
XinyueChen
Keyword(s):  
Comparative Analysis ◽  
3D Visualization ◽  
Three Dimensional ◽  
Volumetric Analysis ◽  
Lateral Approach ◽  
Surgical Anatomy ◽  
Far Lateral Approach ◽  
Far Lateral ◽  
The Difference ◽  
Ct Data

Abstract Background The three-dimensional (3D) visualization model has ability to quantify the surgical anatomy of far-lateral approach. This study was designed to disclose the relationship between surgical space and exposed tissues in the far-lateral approach by the volumetric analysis of 3D model. Methods The 3D skull base models were constructed using MRI and CT data of 15 patients (30 sides) with trigeminal neuralgia. Surgical corridors of the far-lateral approach were simulated by triangular pyramids to represent two surgical spaces exposing bony and neurovascular tissues. Volumetric comparison of surgical anatomy was performed using pair t test. Results The morphometric results were almost the same in the two surgical spaces except the vagus nerve (CN X) exposed only in one corridor, whereas the volumetric comparison represented the statistical significant differences of surgical space and bony and neurovascular tissues involved in the two corridors (P<0.001). The differences of bony and neurovascular tissues failed to equal the difference of surgical space. Conclusions For far-lateral approach, the increase of exposure for the bony and neurovascular tissues is not necessarily matched with the increase of surgical space. The volumetric comparative analysis is helpful to provide more detailed anatomical information in the surgical design.

scholarly journals Volumetric comparative analysis of anatomy through far-lateral approach: surgical space and exposed tissues

2021 ◽  
Author(s):  
Ke Tang ◽  
Feng Xu ◽  
Xiaodong Yuan ◽  
Yang Li ◽  
Xinyue Chen
Keyword(s):  
Comparative Analysis ◽  
3D Visualization ◽  
Three Dimensional ◽  
Volumetric Analysis ◽  
Lateral Approach ◽  
Surgical Anatomy ◽  
Far Lateral Approach ◽  
Far Lateral ◽  
The Difference ◽  
Ct Data

Abstract Background The three-dimensional (3D) visualization model has ability to quantify the surgical anatomy of far-lateral approach. This study was designed to disclose the relationship between surgical space and exposed tissues in the far-lateral approach by the volumetric analysis of 3D model. Methods The 3D skull base models were constructed using MRI and CT data of 15 patients (30 sides) with trigeminal neuralgia. Surgical corridors of the far-lateral approach was simulated by triangular pyramids to represent two surgical spaces exposing bony and neurovascular tissues. Volumetric comparison of surgical anatomy was performed using pair t test. Results The morphometric results were almost the same in the two surgical spaces except the vagus nerve (CN X) exposed only in one corridor. Whereas, the volumetric comparison represented the statistical significant differences of surgical space, and bony and neurovascular tissues involved in the two corridors (P༜0.001). The differences of bony and neurovascular tissuesfailed to equal the difference of surgical space. Conclusions For far-laterl approach, the increase of exposure for the bony and neurovascular tissues is not necessarilymatched with the increase of surgical space. The volumetric comparative analysis is helpful to provide more detailed anatomical information in the surgical design.

scholarly journals Volumetric Comparative Analysis of Anatomy Through Far-Lateral Approach: Surgical Space and Exposed Tissues

2021 ◽  
Author(s):  
Ke Tang ◽  
Xu Feng ◽  
Xiaodong Yuan ◽  
Yang Li ◽  
Xinyue Chen
Keyword(s):  
Comparative Analysis ◽  
3D Visualization ◽  
Three Dimensional ◽  
Volumetric Analysis ◽  
Lateral Approach ◽  
Surgical Anatomy ◽  
Far Lateral Approach ◽  
Far Lateral ◽  
The Difference ◽  
Ct Data

Abstract Objective The three-dimensional (3D) visualization model has ability to quantify the surgical anatomy of far-lateral approach. This study was designed to disclose the relationship between surgical space and exposed tissues in the far-lateral approach by the volumetric analysis of 3D model. Methods The 3D skull base modelswere constructed using MRI and CT data of 15 patients (30 sides) with trigeminal neuralgia. Surgical corridorsof the far-lateral approach was simulated by triangular pyramids to represent two surgical spaces exposing bony and neurovascular tissues. Volumetric comparison of surgical anatomy was performed using pair t test. Results The morphometric results were almost the same in the two surgical spaces except the vagus nerve (CN X) exposed only in one corridor. Whereas, the volumetric comparison represented the statistical significant differences of surgical space, and bony and neurovascular tissues involved in the two corridors (P༜0.001). The differences of bony and neurovascular tissuesfailed to equal the difference of surgical space. Conclusions For far-laterl approach, the increase of exposure for the bony and neurovascular tissues is not necessarilymatched with the increase of surgical space. The volumetric comparative analysis is helpful to provide more detailed anatomical information in the surgical design.

Modeling Dynamic Behaviors of Reticulated Ceramic/Metal Composites (RCMC)

2012 ◽  
Vol 512-515 ◽  
pp. 1051-1057
Author(s):  
Guo Ju Li ◽  
Qun Bo Fan ◽  
J.Y. An ◽  
Fu Chi Wang
Keyword(s):  
Phase Distribution ◽  
Dynamic Properties ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Metallic Matrix ◽  
High Strength ◽  
Metal Composites ◽  
Dynamic Behaviors ◽  
Distribution Shape ◽  
Shape Ratio

Reticulated ceramic/metal composites (RCMC) are characterized by the ceramic skeleton and metallic matrix both continuous in three-dimensional space, and this special structure makes full use of the ceramic phase’s high strength and the metal phase’s toughness. Correspondingly, the deformation and damages mechanisms of RCMC under dynamic load conditions are very complicated and the related studies are quite important. In the current study, the dynamic properties of RCMC are investigated by using finite element methods based on the factitious microstructures of SiC/Al composites. The ceramic/metal interface is induced by employing a “constrained-tie-break” method, so as to study the effects of interface when suffering from a dynamic impact loads. Effects of the phase distribution, shape, ratio, as well as the size are systematically analyzed. The methods proposed in this paper would be helpful for predicting the dynamic behaviors of RCMC, and developing new ceramic/metal composites.

scholarly journals Experimental Study on Uniaxial Compression of Bamboo Nodes Using 3D Scanning Technique

2019 ◽  
Vol 275 ◽  
pp. 01022
Author(s):  
Xinmiao Meng ◽  
Han Sun ◽  
Yuyang Cao ◽  
Peng Feng
Keyword(s):  
Three Dimensional ◽  
High Strength ◽  
Experimental Results ◽  
High Yield ◽  
Cross Sectional ◽  
Modeling Technology ◽  
Cross Section Area ◽  
Bamboo Nodes ◽  
The Cross ◽  
The Difference

Bamboo is a kind of ecological building material for its physical and mechanical characteristics, such as fast growth, high yield, high strength, high toughness and good environmental performance. However, there are few studies on the influence of bamboo node structure about the mechanical properties of bamboo, and it is difficult to accurately determine the cross-section area of the bamboo node. In this paper, the three-dimensional scanner was combined with the reverse modeling technology to accurately obtain the cross-sectional area of the bamboo node. The bamboo node was subjected to axial compression test. Based on the experimental results, it was confirmed that the compressive strength of the bamboo node increased from the bottom to the top. The experimental results also showed that the difference in the degree of cracks has an effect on the bamboo break mode. Bamboo nodes with severe cracks and uneven distribution on the surface had the largest degree of expansion at the original deep cracks or the original surface through cracks. Bamboo nodes with slight cracks and even distribution or without cracks on the surface were uniformly expanding at the lower part when they were broken.

Defocus ramp correction in spot-scan imaging

1992 ◽  
Vol 50 (1) ◽  
pp. 130-131
Author(s):  
Kenneth H. Downing
Keyword(s):  
Computer Control ◽  
Three Dimensional ◽  
Sufficient Accuracy ◽  
Objective Lens ◽  
Electron Crystallography ◽  
Contrast Transfer Function ◽  
Tilt Axis ◽  
Specimen Height ◽  
The Difference ◽  
Envelope Functions

Three-dimensional structures of a number of samples have been determined by electron crystallography. The procedures used in this work include recording images of fairly large areas of a specimen at high tilt angles. There is then a large defocus ramp across the image, and parts of the image are far out of focus. In the regions where the defocus is large, the contrast transfer function (CTF) varies rapidly across the image, especially at high resolution. Not only is the CTF then difficult to determine with sufficient accuracy to correct properly, but the image contrast is reduced by envelope functions which tend toward a low value at high defocus.We have combined computer control of the electron microscope with spot-scan imaging in order to eliminate most of the defocus ramp and its effects in the images of tilted specimens. In recording the spot-scan image, the beam is scanned along rows that are parallel to the tilt axis, so that along each row of spots the focus is constant. Between scan rows, the objective lens current is changed to correct for the difference in specimen height from one scan to the next.

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