scholarly journals 3D Printing with Mixed Powders of Boron Carbide and Al Alloy

2020 ◽  
Vol 10 (9) ◽  
pp. 3055
Author(s):  
Shuang Bai ◽  
Hyeong Jae Lee ◽  
Jian Liu
Keyword(s):  
Aluminum Alloy ◽  
Boron Carbide ◽  
Three Dimensional ◽  
Melting Process ◽  
Wall Structure ◽  
Al Alloy ◽  
Thin Wall ◽  
Laser Additive Manufacturing ◽  
Scan Speed ◽  
Scan Pattern

Laser additive manufacturing with mixed powders of boron carbide and aluminum alloy is investigated. Parameters such as laser power, scan speed, scan pattern, and hatching space are systematically evaluated and optimized to obtain the desired density and porosity. These results show that the AM part contains 20 wt% boron carbide and 80 wt% aluminum alloy, which are well mixed and synthesized during the melting process. Its mechanical properties are close to those of aluminum. A thin-wall structure based two dimensional and three dimensional radial collimators were fabricated with well-controlled geometry for neutron scattering measurement.

Gold Nanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy and Three-Dimensional Contour Imaging of an Aluminum Alloy

2020 ◽  
pp. 000370282097304
Author(s):  
Amal A. Khedr ◽  
Mahmoud A. Sliem ◽  
Mohamed Abdel-Harith
Keyword(s):  
Gold Nanoparticles ◽  
Aluminum Alloy ◽  
Three Dimensional ◽  
Plasma Temperature ◽  
Spectral Lines ◽  
Laser Induced Breakdown Spectroscopy ◽  
Al Alloy ◽  
Boltzmann Plot ◽  
Breakdown Spectroscopy ◽  
Laser Induced Breakdown

In the present work, nanoparticle-enhanced laser-induced breakdown spectroscopy was used to analyze an aluminum alloy. Although LIBS has numerous advantages, it suffers from low sensitivity and low detection limits compared to other spectrochemical analytical methods. However, using gold nanoparticles helps to overcome such drawbacks and enhances the LIBS sensitivity in analyzing aluminum alloy in the current work. Aluminum was the major element in the analyzed samples (99.9%), while magnesium (Mg) was the minor element (0.1%). The spread of gold nanoparticles onto the Al alloy and using a laser with different pulse energies were exploited to enhance the Al alloy spectral lines. The results showed that Au NPs successfully improved the alloy spectral lines intensity by eight times, which could be useful for detecting many trace elements in higher matrix alloys. Under the assumption of local thermodynamic equilibrium, the Boltzmann plot was used to calculate the plasma temperature. Besides, the electron density was calculated using Mg and H lines at Mg(I) at 285.2 nm and Hα(I) at 656.2 nm, respectively. Three-dimensional contour mapping and color fill images contributed to understanding the behavior of the involved effects.

scholarly journals Influence of Thin-Wall Structure on Stress Distribution of Curvic Couplings

2015 ◽  
Vol 45 (3) ◽  
pp. 37-52
Author(s):  
Shuxia Yuan ◽  
Youyun Zhang ◽  
Yongsheng Zhu
Keyword(s):  
Stress Distribution ◽  
Three Dimensional ◽  
Wall Structure ◽  
External Diameter ◽  
Thin Wall ◽  
Contact Interface ◽  
Contact Algorithm ◽  
Stress Fluctuation ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Abstract The objective of this paper is to investigate the influence of transition structure between curvic teeth and disk on stress distribution of curvic couplings, and provide data to help improving the design of curvic couplings. In this work, the three-dimensional finite element method was used, and Augmented Lagrange Algorithm was adopted to the contact algorithm during the analysis. According to the results of this paper, designing thin-wall structure reasonably can avoid detaching of contact interface at external diameter during preload process; reduce stress fluctuation of curvic teeth caused by circumferential bolts structure; and balance stress difference of each contact pair caused by different disk quality under the action of the centrifugal force.

Fabrication of Cu-Al-Ni Shape Memory Alloy by Selective Laser Melting Process

2018 ◽  
Vol 941 ◽  
pp. 1570-1573
Author(s):  
Ken Imai ◽  
Toshi Taka Ikeshoji ◽  
Kazuya Nakamura ◽  
Motonori Nishida ◽  
Yuji Sugitani ◽  
...  
Keyword(s):  
Shape Memory ◽  
Selective Laser Melting ◽  
Elastic Anisotropy ◽  
Copper Alloys ◽  
Three Dimensional ◽  
Melting Process ◽  
Laser Melting ◽  
Good Shape ◽  
Ni Alloy ◽  
Scan Speed

Additive manufacturing (AM) is a prominent technology in the industrial fields such as aerospace, medical, automotive and so on. Especially, selective laser melting (SLM) process is available to create three-dimensional complicated structures of various alloys such as stainless steel, titanium alloy, aluminium alloy, nickel-based superalloy and so on. And also, copper and copper alloys are used as a material for products with complicated shape, electrical components, and a heat exchanger because of having the high electrical conductivity and the high thermal conductivity. It is known that copper alloys show a good shape memory behaviour by adding Al, Ni and Zn. Especially, Cu-Al-Ni alloy shows a good shape memory properties at high temperature. However, it is difficult to fabricate high-density Cu-Al-Ni alloy by the SLM process. This is mainly because Cu-Al-Ni alloy has high elastic anisotropy and brittleness in polycrystalline state. In this research, the optimum fabrication condition of Cu-Al-Ni alloy by SLM process was investigated. The optimum laser power and scan speed were able to be found by evaluating the surface morphology, density and microstructure of the as-build specimens.The maximum density of the as-built specimen was 99.47%.

scholarly journals Femtosecond Laser Additive Manufacturing of Multi-Material Layered Structures

2020 ◽  
Vol 10 (3) ◽  
pp. 979 ◽  
Author(s):  
Shuang Bai ◽  
Jian Liu
Keyword(s):  
Additive Manufacturing ◽  
Fuel Cell ◽  
Layer Structure ◽  
Single Step ◽  
Lanthanum Strontium Manganite ◽  
Laser Additive Manufacturing ◽  
Scan Speed ◽  
Femtosecond Fiber Lasers ◽  
Anode Support ◽  
Scan Pattern

Laser additive manufacturing (LAM) of a multi-material multi-layer structure was investigated using femtosecond fiber lasers. A thin layer of yttria-stabilized zirconia (YSZ) and a Ni–YSZ layer were additively manufactured to form the electrolyte and anode support of a solid oxide fuel cell (SOFC). A lanthanum strontium manganite (LSM) layer was then added to form a basic three layer cell. This single step process eliminates the need for binders and post treatment. Parameters including laser power, scan speed, scan pattern, and hatching space were systematically evaluated to obtain optimal density and porosity. This is the first report to build a complete and functional fuel cell by using the LAM approach.

scholarly journals Characterization of Microstructure, Precipitations and Microsegregation in Laser Additive Manufactured Nickel-Based Single-Crystal Superalloy

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2300 ◽  
Author(s):  
Zhaoyang Liu ◽  
Jiayang Shu
Keyword(s):  
Heat Treatment ◽  
Single Crystal ◽  
Treatment Process ◽  
Three Dimensional ◽  
Subsequent Heat Treatment ◽  
Single Crystal Superalloy ◽  
Wall Structure ◽  
Thin Wall ◽  
Heat Treatment Process ◽  
Dimensional Network

In this study, the microstructure, precipitations, and microsegregation in the laser additive manufactured thin-wall structure of a single-crystal superalloy are synthetically characterized. The influence of a subsequent heat treatment on the microstructure and precipitations is discussed. The results show that under the given processing conditions, the single-crystal microstructure is regenerated perfectly with small misorientation angles in the thin-wall structure. The crystal morphology shows obvious diversity and instability with the incremental height of thin-wall structure. With the increase of manufacturing height, both the primary and secondary dendritic arm spacings of epitaxial columnar dendrites first increase rapidly and then reach a dynamic balanced state. The distribution of precipitations and pores keeps symbiosis in the interdendritic region and shows periodic band characteristic with high density in the band region and low density in the inner region of plate layers. The microsegregation of element atoms in the microstructure shows a three-dimensional network distribution. The concentration of element atoms keeps good consistency with high value in the three-dimensional network and nearly standard value in the outside region. The subsequent heat treatment process contributes to the occupation of as-processed pores by the expanded mature precipitations with good blocky shape. Further optimization of the heat treatment process for improving the lattice coherency of precipitated γ’ phase and γ matrix in the laser additive manufactured single-crystal superalloy is needed and valuable.

Exploration of cell wall architecture with the rapid-freeze deep-etch technique

1993 ◽  
Vol 51 ◽  
pp. 128-129
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Chris Hawes
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cell Biology ◽  
Molecular Model ◽  
Three Dimensional ◽  
Secretory Activity ◽  
Wall Structure ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

Corrosion study on AA5083 aluminum alloy - boron carbide composite

2019 ◽  
Vol 16 ◽  
pp. 1124-1129 ◽  
Author(s):  
N. Vasudevan ◽  
G.B. Bhaskar ◽  
A. Rajendra Prasad ◽  
S.M. Suresh
Keyword(s):  
Aluminum Alloy ◽  
Boron Carbide ◽  
Corrosion Study ◽  
Carbide Composite ◽  
Aa5083 Aluminum Alloy

Hole Expansion by Using Al-Alloy Specimen and 0.45% Carbon Steel Specimen

2010 ◽  
Vol 452-453 ◽  
pp. 601-604
Author(s):  
Muhammed Sohel Rana ◽  
Md. Shafiul Ferdous ◽  
Chobin Makabe ◽  
Masaki Fujikawa
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Carbon Steel ◽  
Cold Work ◽  
Fatigue Crack Initiation ◽  
Steel Specimen ◽  
Expansion Method ◽  
Al Alloy ◽  
2024 Aluminum Alloy ◽  
Cold Worked

The enhancement method of fatigue life and the crack initiate and growth behavior of a holed specimen was investigated by using the 2024 Aluminum alloy and 0.45% Carbon steel. The purpose of present study is to propose a simple technical method for enhancement of fatigue life in a notched specimen. Also, the effect of local plastic deformation by cold work on fatigue crack initiation behavior was examined. This paper presents a basic experimental kinematic cold expansion method by inserting and removing a pin through the specimen hole. The shape of cross-section of pin was a circle or an ellipse. It was shown that the fatigue life of the specimen with the cold-worked hole was longer than that of the specimen with non-cold-worked hole for the case of same stress level in aluminum alloy and carbon steel. Also, the fatigue strength was higher in the case of the cold expanded hole. In this study, a methodology of lengthening of fatigue life of holed specimen is shown. Also, the improvement conditions of fatigue life were significantly affected by shape of pin, local hardening and residual stress conditions. The fatigue life improvement of the damaged component of structures was studied.

Early changes in coronary artery wall structure detected by microcomputed tomography in experimental hypercholesterolemia

2007 ◽  
Vol 293 (3) ◽  
pp. H1997-H2003 ◽  
Author(s):  
Xiang-Yang Zhu ◽  
Michael D. Bentley ◽  
Alejandro R. Chade ◽  
Erik L. Ritman ◽  
Amir Lerman ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Coronary Artery ◽  
Growth Factor ◽  
Three Dimensional ◽  
Wall Structure ◽  
Vascular Endothelial ◽  
Micro Ct ◽  
Artery Wall ◽  
Coronary Artery Wall ◽  
Endothelial Growth Factor

Changes in the structure of the artery wall commence shortly after exposure to cardiovascular risk factors, such as hypercholesterolemia (HC), but may be difficult to detect. The ability to study vascular wall structure could be helpful in evaluation of the factors that instigate atherosclerosis and its pathomechanisms. The present study tested the hypothesis that early morphological changes in coronary arteries of hypercholesterolemic (HC) pigs can be detected using the novel X-ray contrast agent OsO4 and three-dimensional micro-computed tomography (CT). Two groups of pigs were studied after they were fed a normal or an HC (2% cholesterol) diet for 12 wk. Hearts were harvested, coronary arteries were injected with 1% OsO4 solution, and cardiac samples (6-μm-thick) were scanned by micro-CT. Layers of the epicardial coronary artery wall, early lesions, and perivascular OsO4 accumulation were determined. Leakage of OsO4 from myocardial microvessels was used to assess vascular permeability, which was correlated with immunoreactivity of vascular endothelial growth factor in corresponding histological cross sections. OsO4 enhanced the visualization of coronary artery wall layers and facilitated detection of early lesions in HC in longitudinal tomographic sections of vascular segments. Increased density of perivascular OsO4 in HC was correlated with increased vascular endothelial growth factor expression and suggested increased microvascular permeability. The use of OsO4 as a contrast agent in micro-CT allows three-dimensional visualization of coronary artery wall structure, early lesion formation, and changes in vascular permeability. Therefore, this technique can be a useful tool in atherosclerosis research.

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