Microstructural Investigations on ATIG and FBTIG Welding of AA 2219 T87 Aluminum Alloy

2014 ◽  
Vol 592-594 ◽  
pp. 489-493 ◽  
Author(s):  
A.V. Santhana Babu ◽  
P.K. Giridharan ◽  
P. Ramesh Narayanan ◽  
S.V.S. Narayana Murty
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Aluminum Alloys ◽  
Scanning Electron Microscope ◽  
Key Words ◽  
Energy Dispersive Spectroscopy ◽  
Welding Process ◽  
Microstructural Investigation ◽  
Cracking Tendency ◽  
Scanning Electron

Limitation in penetration depth is a concern in conventional TIG welding process. To improve penetration capability of TIG process, both Activated TIG (ATIG) and Flux Bounded TIG (FBTIG) are investigated in aluminum alloy AA 2219 T87. Undesirable arc wandering and cracking tendency are observed in ATIG welds. Microstructural investigation reveals ATIG welds are prone for liquation cracks. Morphology of the cracks along with the attributable factors are explained with optical and SEM (Scanning Electron Microscope) micrographs. Energy Dispersive Spectroscopy (EDS) results are also presented to explain the solute enrichment in the grain boundaries of the ATIG welds. FBTIG is found to produce good quality welds and is more suitable for welding aluminum alloys. Key words: Flux Assisted TIG; ATIG; FBTIG; Penetration Improvement; Microstructure; AA2219.

scholarly journals Pengaruh Suhu Kalsinasi terhadap Karakteristik Komposit Forsterit-Karbon Tersintesis dalam Medium Gas Argon

2020 ◽  
Vol 16 (2) ◽  
pp. 12
Author(s):  
Solihudin Solihudin ◽  
Haryono Haryono ◽  
Atiek Rostika Noviyanti ◽  
Muhammad Rizky Ridwansyah
Keyword(s):  
Fourier Transform ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Rice Husk ◽  
Energy Dispersive Spectroscopy ◽  
Carbon Composite ◽  
X Ray Diffraction ◽  
Argon Gas ◽  
X Ray ◽  
Scanning Electron

<p>Komposit forsterit-karbon merupakan salah satu material modifikasi dari forsterit yang berpotensi memiliki sifat isolator panas baik. Karbon dalam komposit dapat mengisi cacat titik pada kristal forsterit. Arang sekam padi (residu gasifikasi) mengandung SiO2 amorf dan karbon yang tinggi. Penelitian ini bertujuan menentukan pengaruh suhu kalsinasi dalam medium gas inert (dengan pengaliran gas argon) terhadap karakteristik komposit forsterit-karbon dari arang sekam padi dan magnesium karbonat. Metode penelitian meliputi preparasi arang sekam padi hasil gasifikasi, dan sintesis forsterit-karbon. Proses sintesis komposit forsterit karbon dilakukan dengan cara mencampurkan arang sekam padi dengan kalium karbonat pada rasio mol magmesium terhadap silikon sebesar 2 : 1 kemudian dikalsinasi dengan suhu divariasikan (700, 800, 900, dan 1000 oC). Selanjutnya sampel hasil sintesis dikarakterisasi dengan Fourier-transform infrared (FTIR), X-ray diffraction (XRD), dan scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). Hasil karakterisasi dengan FTIR dan XRD diperoleh kesimpulan bahwa forsterit mulai terbentuk pada suhu kalisiasi 800 oC dan sempurna pada suhu 1000 oC, karenanya komposit yang terbentuk pada 1000 oC dimungkinkan sebagai forsterit-karbon, di mana unsur-unsur yang terkandung ditunjukkan oleh SEM-EDS.</p><p> </p><p><strong>The Effect of Calcination Temperature on the Characteristics of Forsterite-Carbon Composites Synthesized in Argon Gas Medium</strong>. Forsterite-carbon composite is one of the material modifications of forsterite, which potentially has a good heat insulation property. Carbon in composites can fill point defects in forsterite crystals. Rice husk charcoal, as gasification residues, contains high amorphous SiO2 and carbon. This study aims to determine the effect of temperature on the calcination of a mixture of rice husk charcoal and magnesium carbonate under an inert gas (argon gas) on the characteristics of the forsterite-carbon composite produced. The experimental research performed includes the preparation of gasified rice husk charcoal and the synthesis of the carbon-forsterite composite. The synthesis process of the carbon-forsterite composites was carried out by mixing rice husk charcoal with potassium carbonate at a mole ratio of magnesium to silicon of 2 : 1. The mixture was then calcined with varying temperatures (700, 800, 900, and 1000 °C). Furthermore, the synthesized sample was characterized by Fourier-transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope-energy dispersive spectroscopy (SEM-EDS). The FTIR and XRD analysis show that the forsterites began to form at a calcination temperature of 800 °C and perfectly formed at a temperature of 1000 °C; therefore, the composite formed at 1000 °C is possible as forsterite-carbon, in which the contained elements were indicated by SEM-EDS.</p>

X-Ray Energy Dispersive Spectroscopy in the Environmental Scanning Electron Microscope

1998 ◽  
Vol 4 (S2) ◽  
pp. 182-183
Author(s):  
John F. Mansfield ◽  
Brett L. Pennington
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Energy Dispersive Spectroscopy ◽  
Primary Electron ◽  
Environmental Scanning ◽  
Primary Electron Beam ◽  
X Ray ◽  
Environmental Sem ◽  
Scanning Electron

The environmental scanning electron microscope (Environmental SEM) has proved to be a powerful tool in both materials science and the life sciences. Full characterization of materials in the environmental SEM often requires chemical analysis by X-ray energy dispersive spectroscopy (XEDS). However, the spatial resolution of the XEDS signal can be severely degraded by the gaseous environment in the sample chamber. At an operating pressure of 5Torr a significant fraction of the primary electron beam is scattered after it passes through the final pressure limiting aperture and before it strikes the sample. Bolon and Griffin have both published data that illustrates this effect very well. Bolon revealed that 45% of the primary electron beam was scattered by more than 25 μm in an Environmental SEM operating at an accelerating voltage of 30kV, with a water vapor pressure of 3Torr and a working distance of 15mm.

scholarly journals Comparison of pollen morphological structures of some taxa belonging to Asparagus L. and Fritillaria L. (Liliaceae) from Turkey

1970 ◽  
Vol 36 (2) ◽  
pp. 111-120 ◽  
Author(s):  
H Ozler ◽  
S Pehlivan
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Key Words ◽  
Transmission Electron Microscope ◽  
Light Microscope ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Exine Sculpture ◽  
Transmission Electron ◽  
Scanning Electron

Pollen grains of 20 taxa from two genera of the Liliaceae were examined and compared by LM (light microscope), SEM (scanning electron microscope) and pollens of four taxa were also examined with TEM (transmission electron microscope). Pollen grains shed as monads. They are monosulcate and ellipsoidal. Fritillaria crassifolia subsp. crassifolia Freyn & Smt. sometimes sheds the pollen as dyads. Exine is semitectate and the tectum is perforate. Columellae are simplicolumellate. Ectexine is thicker than endexine. Exine sculpture (ornamentation) is reticulate, reticulate-rugulate, rugulate and retipilate in Asparagus pollens and reticulate, suprareticulate, rugulate-reticulate and striate-reticulate in Fritillaria pollens. Sulcus extends from distal to proximal in some pollens of Asparagus and Fritillaria.   Key words: Asparagus, Fritillaria, Liliaceae, Pollen morphology DOI = 10.3329/bjb.v36i2.1498 Bangladesh J. Bot. 36(2): 111-120, 2007 (December)

Segregation and Precipitation Behavior of Phosphorus in a Ni-Fe-Cr Base Wrought Superalloy

2018 ◽  
Vol 913 ◽  
pp. 150-156 ◽  
Author(s):  
Sha Zhang ◽  
An Wen Zhang ◽  
Wei Yang Wang ◽  
Xin Xin ◽  
Kai Zhang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Grain Boundaries ◽  
Energy Dispersive Spectroscopy ◽  
Peak Temperature ◽  
Energy Dispersive ◽  
Precipitation Behavior ◽  
Temperature Range ◽  
Precipitation Temperature ◽  
Scanning Electron

The segregation and precipitation behavior of phosphoruswas studied in aNi-Fe-Cr base wroughtsuperalloy. The precipitation behavior of phosphides in the alloy contained 0.025% Pwas examined after soaking at 750-1080°C to determine the precipitation temperature range of MNP-type phosphide. The microstructuresunder these various conditions wereinvestigated by scanning electron microscope(SEM) and energy dispersive spectroscopy (EDS). The precipitation temperature of the phosphide in the alloy was determined to be in the range of 850-1040 °C and the precipitation peak temperature was around 980°C.In addition, the melting temperatureof the phosphide was determined to be between 1200 °C and 1250 °C. The current results indicate the tendency of phosphorus segregated at grain boundaries.

Metal Impurity Mapping in Semiconductor Materials Using X-Ray Fluorescence

1998 ◽  
Vol 510 ◽  
Author(s):  
S.A. McHugo ◽  
A.C. Thompson ◽  
H. Padmore
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Energy Dispersive Spectroscopy ◽  
Semiconductor Materials ◽  
Metal Impurity ◽  
Standard Samples ◽  
X Ray ◽  
Metal Impurities ◽  
Cobalt Nickel ◽  
Scanning Electron

AbstractWe present x-ray fluorescence (XRF) results from studies of metal impurities in silicon. A synchrotron-based XRF microprobe, with μm spatial resolution, was used to detect and map the impurities. The sensitivity of the XRF microprobe was determined for copper and iron in silicon using well-characterized standard samples. We have concluded the system can detect one iron or copper precipitate in silicon with a radius of ≈14nm. This sensitivity pertains to other relevant impurities in silicon, such as, chromium, manganese, cobalt, nickel and gold. Furthermore, we have detected and spatially mapped metal impurity precipitates in silicon, which are undetectable by Energy Dispersive Spectroscopy in a Scanning Electron Microscope. These results exhibit the extraordinary sensitivity of the XRF microprobe for metal impurities in semiconductors.

Age-Hardening Response of Mg-Al-Sn Alloys

2015 ◽  
Vol 828-829 ◽  
pp. 250-255
Author(s):  
Abu Syed Humaun Kabir ◽  
Jing Su ◽  
Mehdi Sanjari ◽  
In Ho Jung ◽  
Stephen Yue
Keyword(s):  
Electron Microscope ◽  
Aluminum Alloys ◽  
Scanning Electron Microscope ◽  
Magnesium Alloys ◽  
Isothermal Aging ◽  
Precipitation Hardening ◽  
Metallic Alloys ◽  
Mg Alloys ◽  
Age Hardening ◽  
Scanning Electron

Precipitation hardening has been used before as one of the most effective strengthening methods for many metallic alloys. However, this method has not been studied completely in magnesium alloys, and the numbers of precipitation hardenable wrought Mg alloys are still very limited compared to aluminum alloys and steels. The age hardening responses of Mg-Al-Sn alloys in cast-homogenized condition were investigated by isothermal aging at 200°C for prolonged time. It was found that hardness can be improved significantly for the alloy with higher amounts of tin. The improvement in hardness was reasoned by the formation of precipitates. The shapes and morphology of the precipitates were different depending on the orientations of the grains. The precipitates were characterized by scanning electron microscope.

An Investigation on the Impurities of Aluminum Alloy in Melt Furnace

2010 ◽  
Vol 97-101 ◽  
pp. 1045-1048
Author(s):  
Zheng Bin Xu ◽  
Yong Zhi Zou ◽  
Wen Chao Wang ◽  
Xing Zhi Pang ◽  
Jian Min Zeng
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Elemental Carbon ◽  
Energy Dispersive Spectrometer ◽  
Furnace Wall ◽  
Sio2 Particle ◽  
A357 Alloy ◽  
Unknown Phase ◽  
Scanning Electron

The scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) were used to characterize samples prepared from the surface scum of melt, the middle flake residues on the furnace wall and the “bottom bulk” after the A357 alloy pouring. The morphology and impurities composition of these features were investigated. Some of particles and regions in samples during the analyses were also studied in detail. The results of analyses show that the surface scum of melt include Al2O3, MgO or MgAl2O4; the impurities of the middle flake residues is comprised of Al2O3, MgO or MgAl2O4, as well as SiO2 particle, Al9Fe2Si2 compound and dimple like C-rich areas; the bottom bulk contains C-rich impurities such as Al4C3 or some of unknown phase or elemental carbon.

The Surface Deformation of Aluminum Compressed With Viscous Lubricants

1974 ◽  
Vol 96 (4) ◽  
pp. 591-594 ◽  
Author(s):  
D. D. Ratnagar ◽  
H. S. Cheng ◽  
J. A. Schey
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Finish ◽  
Surface Deformation ◽  
Surface Roughening ◽  
6061 Aluminum Alloy ◽  
Clear Delineation ◽  
Lubricant Viscosity ◽  
Scanning Electron

The influences of lubricant viscosity and loading velocity on the surface finish of plastically compressed 6061 aluminum alloy cylinders were studied. Specimens with polished end faces were subjected to compression between two flat, chromium plated dies, with lubricants of a viscosity ranging from 42 cp to 1207 cp at 38 deg C. The deformed surfaces were studied under a scanning electron microscope and by stylus tracings and CLA readings. With the lighter lubricants surface roughening resulted from preferential yielding leading to a clear delineation of grain boundaries and slip lines. With the heavier lubricants, localized “hydrodynamic pockets” formed in addition to the above features. The depth of pockets increased with viscosity and/or velocity.

scholarly journals ANALISIS PENGARUH LAJU PUTAR TERHADAP KOROSI BAJA KARBON API 5LX65 MENGGUNAKAN METODE ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY

2012 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Agus Solehudin ◽  
Asep Lukman
Keyword(s):  
Electron Microscope ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Scanning Electron Microscope ◽  
Energy Dispersive Spectroscopy ◽  
Electrochemical Impedance ◽  
Energy Dispersive ◽  
X Ray ◽  
Scanning Electron

Pada percobaan ini, telah dipelajari pengaruh laju putar terhadap laju korosi baja karbon API 5LX65 yang direndam selama 24 jam dalam larutan NaCl 3,5% + 500 mg/L H2S menggunakan metode EIS (Electrochemical Impedance Spectroscopy) pada suhu 50oC dan pH 4 dengan variasi laju putar 50 rpm, 150 rpm, dan 250 rpm. Hasil percobaan memperlihatkan pergeseran dan penyempitan kurva setengah lingkaran impedansi imaginer terhadap impedansi real, dengan meningkatnya laju putar dari 50 rpm sampai dengan 250 rpm. Hal ini mengindikasikan bahwa aktifitas pelarutan baja meningkat dengan percepatan laju putar. Nilai Cdl meningkat dengan meningkatnya laju putar. Nilai tahanan polarisasi (Rp) semakin menurun dengan meningkatnya laju putar, sementara nilai tahanan larutan (Rs) relatif tidak berubah. Potensial korosi pada laju putar 50 rpm, 150 rpm dan 250 rpm stabil  pada -517 mV hingga -508 mV terhadap Ag/AgCl. Gabungan pengamatan Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS) dan X-Ray Diffractomer (XRD) menunjukkan terbentuknya lapisan produk korosi. Hasil analisis XRD spesimen uji yang dikorosikan pada suhu 50oC selama 24 jam menunjukkan bahwa lapisan produk korosi mengandung besi sulfida (FeS). Morfologi permukaan spesimen ini memperlihatkan adanya korosi sumuran.Kata kunci: laju putar, korosi, baja karbon, EIS, H2S

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