MODIFICATION OF THE CAST STRUCTURE OF AN EN AW 2011 ALLOY WITH HOMOGENIZATION

Aluminium alloys of group 2xxx contain copper as the main alloying element. Copper increases the strength and workability of the alloy, but also reduces the corrosion resistance and weldability. During casting, a nonequilibrium solidification occurs. Therefore, the cast alloy needs to be heat treated with a so-called homogenization process. Homogenization allows us to eliminate crystalline segregations and low-melting eutectics, and also causes changes in the morphology of intermetallic phases. The forming ability is in this way increased. In this research the subject of the investigations was the aluminium alloy with designation EN AW 2011 (AlCuBiPb), whereas the comparative analysis before and after homogenization annealing was made. Homogenization was conducted at 520 °C for 6 h. First, slices from two rods before and after homogenization were cut out, where three samples from each slice of the rod, namely in the middle, on D/4 and at the edge of the slice were prepared. Differential scanning calorimetry (DSC) was performed on all six samples, the results were compared with each other in order to establish the structure homogeneity before and after the homogenization process through the cross-section of the rod. Samples for light (LM) and scanning electron microscopy (SEM) were also prepared, whereas the phase composition and chemical homogeneity were analysed. Using the Thermo-Calc program, the nonequilibrium solidification was simulated and the phase formation during solidification was examined. From the obtained results, it was concluded that the homogenization was carried out successfully, due to a homogeneous chemical distribution in the examined phases and to a fairly homogeneous chemical composition throughout the cross-section of the rod slice.

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Analysis of Chemical Composition Homogeneity in the Cross-section of the Rods Produced from Alloys of 6xxx Group

Materials and Geoenvironment ◽

10.2478/rmzmag-2019-0018 ◽

2020 ◽

Vol 66 (3) ◽

pp. 139-148

Author(s):

Maja Vončina ◽

Peter Cvahte ◽

Ana Kračun ◽

Tilen Balaško ◽

Jožef Medved

Keyword(s):

Corrosion Resistance ◽

Chemical Composition ◽

Cross Section ◽

Cross Sections ◽

Intermetallic Phases ◽

Scanning Calorimetry ◽

Good Corrosion Resistance ◽

Energy Dispersion Spectrometer ◽

High Casting Speed ◽

The Cross

AbstractThe alloys from Al–Mg–Si system provide an excellent combination of mechanical properties, heat treatment at extrusion temperature, good weldability, good corrosion resistance and formability. Owing to the high casting speed of rods or slabs, the solidification is rather non-equilibrium, resulting in defects in the material, such as crystalline segregations, the formation of low-melting eutectics, the unfavourable shape of intermetallic phases and the non-homogeneously distributed alloying elements in the cross-section of the rods or slabs and in the entire microstructure. The inhomogeneity of the chemical composition and the solid solution negatively affects the strength, the formability in the warm and the corrosion resistance, and can lead to the formation of undesired phases due to segregation in the material. In this experimental investigation, the cross-sections of the rods from two different alloys of the 6xxx group were investigated. From the cross-sections of the rods, samples for differential scanning calorimetry (DSC) at three different positions (edge, D/4 and middle) were taken to determine the influence of inhomogeneity on the course of DSC curve. Metallographic sample preparation was used for microstructure analysis, whereas the actual chemical composition was analysed using a scanning electron microscope (SEM) and an energy dispersion spectrometer (EDS).

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Modification of traditional benzoxazine by blending with polyfunctional benzoxazines containing aromatic group and fluorene group

High Performance Polymers ◽

10.1177/0954008320974089 ◽

2020 ◽

pp. 095400832097408

Author(s):

Ting Wang ◽

Zhi-yi Guo ◽

Jun-yi Wang ◽

Abdul Qadeer Dayo ◽

Wen-bin Liu ◽

...

Keyword(s):

Thermal Properties ◽

Cross Section ◽

Alkyl Chain ◽

Mechanical Analysis ◽

Alkyl Chain Length ◽

Curing Process ◽

Scanning Calorimetry ◽

Crosslinking Degree ◽

Good Catalytic Activity ◽

The Cross

A series of polyfunctional benzoxazine monomers containing aromatic and fluorene group (AMFB) were used as modified agents to improve the performance of typical bifunctional bisphenol-A-aniline-based (BA-a) benzoxazine resins. The polymerization behaviors of BA-a/AMFB blends were investigated by using the differential scanning calorimetry (DSC), while the dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were used to analyze the thermomechanical and thermal properties of BA-a/AMFB copolymers [poly(BA-a/AMFB)]. Moreover, the cross-section morphologies of poly(BA-a/AMFB) were observed by scanning electron microscope (SEM). The experimental results showed that BA-a monomer has good catalytic activity for AMFB monomers during the curing process. Compared with BA-a polymer [poly(BA-a)], due to the introduction of heat-resistant fluorene ring and the increase of the crosslinking degree of copolymers, the copolymers showed higher glass transition temperature and better thermal properties. For poly(BA-a/AMFB), the T 5, T 10, and Y c were higher than those of poly(BA-a). With the increase of the alkyl chain length of AMFB monomers, the cross-section creases gradually changed from linear to dendritic, and the number of creases increased significantly, which indicated that the toughness of the copolymers was significantly improved.

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Development of Nitinol Stents: Etching Experiments

Materials Science Forum ◽

10.4028/www.scientific.net/msf.729.240 ◽

2012 ◽

Vol 729 ◽

pp. 240-245 ◽

Cited By ~ 1

Author(s):

Bálint Katona ◽

Péter Nagy ◽

Eszter Bognár ◽

Kristóf Hirschberg

Keyword(s):

Cross Section ◽

Laser Cutting ◽

Chemical Etching ◽

Measurement Data ◽

Etching Time ◽

Cross Section Area ◽

Section Area ◽

Nitinol Stents ◽

Before And After ◽

The Cross

The present study focus on the chemical etching of shape memory nickel-titanium (nitinol) alloy stents made by laser cutting. Application of nitinol stents widely spread in case of atherosclerosis of peripheral vessels. This type of stent has to have appropriate surface quality, flexibility and strength. The aim of chemical etching is removing the burr, which arises during the laser cutting. Etching is one step of the production of stents. The appropriate parameters allow the laser burned surface and most of protruding material removing without significant damage of stent shape. During these experiments etching time was changed. After etching the cross section area was determined by metallographic examinations. The results of the examinations show the relationship between the etching time and the cross-section area. The analysis of measurement data revealed the change of etching velocity. Before and after etching the samples was examined by scanning electron microscopy (SEM). The different surfaces also were compared and the findings were discussed.

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Straightness of U75V 100m Heavy Rail under Deferent Straightening Processes

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.127.105 ◽

2011 ◽

Vol 127 ◽

pp. 105-109

Author(s):

Hao Kang ◽

Wu Di ◽

Xian Ming Zhao

Keyword(s):

Cross Section ◽

Time Interval ◽

Before And After ◽

The Cross ◽

Heavy Rail ◽

Section Dimension

Temperature of the head, the waist, the bottom and angle of the bottom of same heavy rail lying on the cooling bed is tested continuously, time interval is 5min, which can provide the basis for prebending process. Additionally, the U75V 60Kg/m heavy rail straightening processes using the horizontal and edge roll compound straightening machine is discussed in this paper, and contrasts the cross-section dimension and straightness of heavy rail before and after being straightened, which is important to make certain of optimum straightening parameters.

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Microstructure of 7N01 Aluminum Alloy Microalloyed with Er and Zr in the Homogenization Process

Materials Science Forum ◽

10.4028/www.scientific.net/msf.993.123 ◽

2020 ◽

Vol 993 ◽

pp. 123-129

Author(s):

Pei Hao Zhao ◽

Xiao Lan Wu ◽

Kun Yuan Gao ◽

Yu Sheng Ding ◽

Hui Huang ◽

...

Keyword(s):

Aluminum Alloy ◽

Electron Microscope ◽

Cast Alloy ◽

Secondary Phase ◽

Dendritic Segregation ◽

Secondary Phases ◽

Sem Images ◽

Homogenization Process ◽

Transmission Electron ◽

Before And After

The microstructure and segregation of 7N01 aluminum alloy microalloyed with Er and Zr before and after homogenization process at 470 °C for 24 h have been investigated using transmission electron microscope (TEM), and scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscope (EDS) and transmission electron detecter (STEM). SEM images and EDS line scan results showed that there were dendritic segregation of Mg and Zn and micron-sized primary phases along dendrites in the as-cast alloy. The primary phases were mainly Al2Mg3Zn3 containing Al, Zn, Mg and Mn. And a small amount of primary phases were the particles containing Al, Zn, Mg, Mn, Cr and Er and the particles containing Al, Zn, Mg, Er, Mn, Fe and Cr. After homogenization at 470°C for 24 h, dendritic segregation of Mg and Zn was eliminated, Al2Mg3Zn3 and the particles containing Al, Zn, Mg and Mn were basically dissolved. The particles containing Al, Zn, Mg, Mn, Cr and Er and the particles containing Al, Zn, Mg, Er, Mn, Fe and Cr remained. Meanwhile, TEM and STEM images showed that a large number of secondary phases appeared after the homogenization, which were mainly distributed in the inter-dendrite area. EDS results showed that the block-shaped and rod-shaped phases with the width of 10-70 nm and length of 100-500 nm were the particles containing Al, Cr and Mn or Al, Mg, Cr and Mn, and the ellipsoid secondary phase with the size of 50-100 nm was MgZn2.

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ANALISIS DAMPAK NORMALISASI SUNGAI TERHADAP EROSI DAN SEDIMENTASI DI DAERAH PERKOTAAN STUDI KASUS: SUNGAI PESANGGRAHAN, JAKARTA

INDONESIAN JOURNAL OF CONSTRUCTION ENGINEERING AND SUSTAINABLE DEVELOPMENT (CESD) ◽

10.25105/cesd.v2i2.6486 ◽

2020 ◽

Vol 2 (2) ◽

pp. 54

Author(s):

Siti Murniningsih ◽

Alfisalam Ghifari Mustafa

Keyword(s):

Sediment Transport ◽

Water Level ◽

Cross Section ◽

River Flow ◽

Provincial Government ◽

River Region ◽

Before And After ◽

Grain Distribution ◽

The Cross ◽

Gis Software

Flooding is one of the problems that often occurs in the DKI Jakarta area, which one of the causes is the change of land use in watersheds that were originally into development areas. Whereas, its often the cross section of the river will be disrupted due to the loss of the riverbanks and the narrower cross section of the river. In order to overcome this, the Jakarta Provincial Government in 2013 normalized several rivers that crossed the DKI Province and one of them was the Pesanggrahan River which will be further investigated. The purpose of this study is to analyze the effect of river normalization on erosion and sedimentation which will result in changes in the longitudinal and cross section of the river. To get an accurate map of the Watershed Area, Arc-GIS software is used while identification of river flow before and after normalization was carried out based on data from Central Office of River Region Ciliwung-Cisadane, Ministry of Public Works. Sediment samples were taken at 3 points on the river, upstream, middle and downstream, that were reviewed to determine the gradation of the sediment grains. The HEC-RAS application is used to simulate sediment transport on the river section before and after normalization. The simulation results are used to determine the cross section changes due to erosion and sedimentation and to determine the water level in the river. From the water level, the hydraulic radius can be calculated and then carried out sediment transport calculation using Ackers-White equation since the equation using grain distribution from range 0.02 – 4.94 mm. The results it was found that the sediment transport in the upstream point increased 155.11 tons / year, at the midpoint increased 89.64 tons / year and the downstream point decreased 0.28 tons / year.

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CONTROLLED FORMATION OF THE DESIGNED MECHANICAL PROPERTIES OF MACHINE PARTS BY DEFORMATION HARDENING IN THE CONDITIONS OF COMPLEX LOCAL LOADING OF THE DEFORMATION ZONE

Fundamental and Applied Problems of Engineering and Technology ◽

10.33979/2073-7408-2020-340-2-34-42 ◽

2020 ◽

Vol 2 ◽

pp. 34-42

Author(s):

S.Yu. RADCHENKO ◽

V.A. GOLENKOV ◽

D.O. DOROKHOV

Keyword(s):

Mechanical Properties ◽

Cross Section ◽

Deformation Zone ◽

Cast Alloy ◽

Processing Parameters ◽

Local Loading ◽

Technological Parameters ◽

Microhardness Distribution ◽

Deformation Hardening ◽

The Cross

The process of complex local loading of the deformation zone is considered using the example of processing a sleeve made of a bronze alloy, the mechanical properties of the cast alloy under study were determined, and the parameters of the microhardness distribution over the cross section of the processed workpiece were investigated. Plots of the distribution of various microhardness parameters over the cross section are plotted depending on the number of processing cycles. A mathematical model of the process under consideration and its comparison with experimental data is shown. The description of the technique in the form of an algorithm of actions for the appointment of technological parameters. An example is presented in the form of a finished nomogram for the assignment of specific processing parameters to obtain a given hardening depth and value.

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A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073933 ◽

1973 ◽

Vol 31 ◽

pp. 698-699

Author(s):

V. Mizuhira ◽

Y. Futaesaku

Keyword(s):

Cross Section ◽

Tannic Acid ◽

Elastic Fiber ◽

The Other ◽

New Approach ◽

Tissue Block ◽

Active Reaction ◽

The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

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Energy Distribution in Electron Beams

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096096 ◽

1972 ◽

Vol 30 ◽

pp. 568-569

Author(s):

Tamotsu Ohno

Keyword(s):

Electron Beam ◽

Energy Distribution ◽

Cross Section ◽

Integral Curve ◽

Electron Beams ◽

Electron Gun ◽

Angular Divergence ◽

Apparent Increase ◽

Integral Width ◽

The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

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Absolute inner-shell cross section determination for EELS analysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010473x ◽

1988 ◽

Vol 46 ◽

pp. 534-535

Author(s):

P.A. Crozier

Keyword(s):

Cross Section ◽

Cross Sections ◽

Absolute Cross Section ◽

Specimen Thickness ◽

Mass Thickness ◽

Scattering Cross ◽

Before And After ◽

Estimated Error ◽

Scattering Cross Sections ◽

Electron Microscopist

Absolute inelastic scattering cross sections or mean free paths are often used in EELS analysis for determining elemental concentrations and specimen thickness. In most instances, theoretical values must be used because there have been few attempts to determine experimental scattering cross sections from solids under the conditions of interest to electron microscopist. In addition to providing data for spectral quantitation, absolute cross section measurements yields useful information on many of the approximations which are frequently involved in EELS analysis procedures. In this paper, experimental cross sections are presented for some inner-shell edges of Al, Cu, Ag and Au.Uniform thin films of the previously mentioned materials were prepared by vacuum evaporation onto microscope cover slips. The cover slips were weighed before and after evaporation to determine the mass thickness of the films. The estimated error in this method of determining mass thickness was ±7 x 107g/cm2. The films were floated off in water and mounted on Cu grids.

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