Characterization of Casting Defects in Aluminium Alloys

2012 ◽  
Vol 430-432 ◽  
pp. 984-987
Author(s):  
Guo Wu ◽  
Keyna O'Reilly ◽  
Marina Galano
Keyword(s):  
Aluminium Alloys ◽  
Oxide Films ◽  
Melting Process ◽  
Major Type ◽  
Induction Melting ◽  
Liquid Aluminium ◽  
Alumina Crucible ◽  
Oxide Defects ◽  
Scanning Electron

In this paper, typical defects in aluminium alloys cast by conventional pouring of liquid metal into a cylindrical alumina crucible and an induction melting process are characterized by using macroetching, optical microscopy and scanning electron microscopy. Oxide film defects are generated in both processing methods. Oxide films formed during casting are a major type of defect observed in the microstructures of aluminium alloys products. It has been found that pouring of molten metal into a mould and induction stirring lead to different forms of oxide defects. Under induction stirring, such low-density entrained defects are found to be carried to near the surface of the liquid aluminium alloys and submerged surface oxide films become entangled.

Obtention of an Al-Based Composite Material by Direct Fusion of Used Beverage Cans

2012 ◽  
Vol 706-709 ◽  
pp. 271-276 ◽  
Author(s):  
Claudia Carrasco ◽  
C. Montalba ◽  
Carlos Camurri
Keyword(s):  
Composite Material ◽  
Aluminium Alloys ◽  
Metal Matrix ◽  
Mechanical Analysis ◽  
Heat Treated ◽  
Structural Applications ◽  
Metal Matrix Composite Material ◽  
Direct Fusion ◽  
Scanning Electron

In the present study, the fabrication of an Al-based metal matrix composite material obtained directly from the melting of the aluminium used beverage cans in a modified rheocasting process is presented. The analysed operational condition is the shear rate applied to the bath and its influence on the properties of the obtained samples. Additionally, samples were heat treated at two different times. The characterization of the phases obtained in Al-based MMC was made by means of metallography, scanning electron microscopy with energy dispersive spectroscopy and electron microprobe with wavelength dispersion spectroscopy. The results show that some constituents were formed during the fabrication process of the MMC, mainly Al6(Fe, Mn), which are partially transformed during the heat treatment. Additionally, samples were evaluated using dynamic mechanical analysis, and the results suggest that the obtained MMC could have very good mechanical properties, similar or superior to the aluminium alloys commonly used for structural applications such as 6XXX family.

scholarly journals Reoxidation Processes Prediction in Gating System by Numerical Simulation for Aluminium Alloys

2017 ◽  
Vol 17 (3) ◽  
pp. 23-26 ◽  
Author(s):  
M. Brůna ◽  
D. Bolibruchová ◽  
R. Pastirčák
Keyword(s):  
Free Surface ◽  
Aluminium Alloys ◽  
Oxide Films ◽  
Front Tracking ◽  
Gating System ◽  
Liquid Aluminium ◽  
Surface Time ◽  
Filling Pattern ◽  
Entrained Air ◽  
Flow Experiments

Abstract Pouring of liquid aluminium is typically accompanied by disturbance of the free surface. During these disturbances, the free surface oxide films can be entrained in the bulk of liquid, also pockets of air can be accidentally trapped in this oxide films. The resultant scattering of porosity in castings seems nearly always to originate from the pockets of entrained air in oxide films. Latest version of ProCast software allows to identify the amount of oxides formed at the free surface and where they are most likely to end-up in casts. During a filling calculation, ProCast can calculate different indicators which allow to better quantify the filling pattern. The fluid front tracking indicator “Free surface time exposure” has the units [cm2*s]. At each point of the free surface, the free surface area is multiplied by the time. This value is cumulated with the value of the previous timestep. In addition, this value is transported with the free surface and with the fluid flow. Experiments to validate this new functions were executed.

scholarly journals Primary microstructure characterization of Co-20Ni-9Al-7W-3Re-2ti superalloy

2021 ◽  
pp. 44-44
Author(s):  
A. Tomaszewska
Keyword(s):  
Casting Process ◽  
Melting Process ◽  
Alloying Elements ◽  
Technological Problem ◽  
Induction Melting ◽  
Interdendritic Segregation ◽  
Segregation Of Alloying Elements ◽  
Titanium Nickel ◽  
Tungsten Concentration

The characterization of the primary microstructure of the new Co-based superalloy of Co-20Ni-9Al-7W-3Re-2Ti type was shown in this article. The investigated alloy was manufactured by induction melting process from pure feedstock materials. The fundamental technological problem related to Co-Al-W-X multicomponent alloys' casting process is a strong susceptibility to interdendritic segregation of alloying elements, especially tungsten and rhenium. The performed analysis revealed that the observed effect of alloying elements segregation is detectable and much stronger than for Co-9Al-9W and Co-20Ni-7Al-7W alloys, related to titanium, nickel and aluminium migration to inter-dendritic spaces. Consequently, the tungsten concentration gradient between dendritic and interdendritic zones is higher than for Co-9Al-9W and Co-20Ni-7Al-7W alloys. The same situation is in the case of rhenium and cobalt, but Co's concentration in the interdendritic zone is only slightly lower.

Synthesis and Characterization of Cerium- and Lanthanum Containing Bioactive Glass

2017 ◽  
Vol 751 ◽  
pp. 617-628 ◽  
Author(s):  
Md Ershad ◽  
Vikas Kr Vyas ◽  
Sunil Prasad ◽  
Akher Ali ◽  
Ram Pyare
Keyword(s):  
Mechanical Properties ◽  
Fourier Transform ◽  
Bioactive Glass ◽  
Body Fluid ◽  
Synthesis And Characterization ◽  
Ftir Analysis ◽  
Alumina Crucible ◽  
Time Period ◽  
Scanning Electron

Synthesis and characterization of bioglass® of general composition (45-X-Y) SiO2, 24.5 Na2O, 24.5 CaO and 6.0 P2O5 (wt %) was modified by addition of X= (0-1) wt % of CeO2 and Y= (0-1) wt % of La2O3 respectively. These five samples were prepared in alumina crucible via melting route at a temperature of 1400±5 °C with air as a furnace atmosphere. These glass samples were immersed in simulated body fluid (SBF) for different time period and their bioactivity were determined by Fourier transform infrared spectroscopy (FTIR) analysis. Surface morphology was studied by using Scanning electron microscope (SEM). Bioactivity, pH measurement of bioactive glass was carried out and mechanical properties of these glasses increased with increasing concentration of CeO2 and La2O3.

scholarly journals Synthesis and characterization of Ln-123 superconductors

2008 ◽  
Vol 73 (4) ◽  
pp. 479-486 ◽  
Author(s):  
Arturas Zalga ◽  
Remigijus Juskenas ◽  
Algirdas Selskis ◽  
Darius Jasaitis ◽  
Aivaras Kareiva
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Melting Process ◽  
Oxygen Stoichiometry ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Superconducting Compounds ◽  
Scanning Electron

A sol-gel method was applied to prepare precursors for NdBa2Cu3O7-x (Nd-123) and SmBa2Cu3O7-x (Sm-123) superconducting compounds. The sintered products were examined by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The powders sintered at 950 and 1000 ?C showed the formation of monophasic Nd-123 and Sm-123 superconductors. The formation of Nd-123 and Sm-123 phases from the sol-gel derived precursors at higher temperatures (1050 and 1100 ?C), however, did not proceed due to the melting process. The correlation between the TC for different lanthanides (Ln Ho, Nd and Sm) in the Ln-123 compound and orthorhombicity and oxygen stoichiometry were also estimated.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Characterization of Sputtered Films using the Scanning Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 44-45
Author(s):  
R. F. Schneidmiller ◽  
W. F. Thrower ◽  
C. Ang
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Sputtered Films ◽  
Plasma Sputtering ◽  
Microelectronic Devices ◽  
Control Film ◽  
Scanning Electron

Solid state materials in the form of thin films have found increasing structural and electronic applications. Among the multitude of thin film deposition techniques, the radio frequency induced plasma sputtering has gained considerable utilization in recent years through advances in equipment design and process improvement, as well as the discovery of the versatility of the process to control film properties. In our laboratory we have used the scanning electron microscope extensively in the direct and indirect characterization of sputtered films for correlation with their physical and electrical properties.Scanning electron microscopy is a powerful tool for the examination of surfaces of solids and for the failure analysis of structural components and microelectronic devices.

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