scholarly journals Estimating the Internal Oxidation of Ni-Al Alloys

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 48 ◽  
Author(s):  
C.G. Nava-Dino ◽  
A. Martinez-Villafañe

Ni-Al alloys create a cone- shaped figure when there is internal oxide. This behavior was studied by TEM, SEM, X-Ray (XRD), Optical Microscopy and Image Processing. The internal oxide precipitates and its results indicate that this precipitation forms continuous rods in a cone-shaped configuration extending from the surface to the internal oxide front for Ni-Al alloys, whereas for Ni-X (X = Cr, Mo, V, W and Mn) alloys the precipitation is discrete and more irregularly-shaped. Furthermore, in a high atomic percentage (5.18% to 8.67%), the precipitation was rod-like and continuous from the surface to the internal oxide front for all temperature\time conditions. For the Ni-2.47% Al alloy at 800 °C, observations showed a mixture of rod-like and fork like precipitates, whereas after oxidation at 1000 and 1100 °C the precipitation was rod-like and continuous. For the Ni-1.18% Al alloy the aluminum concentration was insufficient for fully continuous precipitation to develop, and the internal oxides were generally acicular-shaped and discontinuous. Images obtained by TEM and, after that, analyzed by image processing allowed us to understand their behavior and the internal oxide patterns.

2019 ◽  
Vol 961 ◽  
pp. 118-125
Author(s):  
Muhammad Syukron ◽  
Zuhailawati Hussein ◽  
Abu Seman Anasyida

The combination of heat treatment, addition of grain refiner and ECAP processing is used to improve mechanical properties and wear resistance of A356 Al alloys with 1.5 wt.% TiB2. The alloys were grouped into as-cast and pre-ECAP annealing. The alloys were characterized with hardness and wear testing, optical microscopy and SEM. The ECAP processing was done through BA route for 4 passes and it improved hardness, distribution of TiB2 and Si particles in the aluminium matrix and increased wear resitance of pre-ECAP annealing specimen.


1999 ◽  
Vol 564 ◽  
Author(s):  
Pei-I Wang ◽  
G. -R. Yang ◽  
S. P. Murarka ◽  
T. -M. Lu

AbstractCu-Al alloys have been recommended for application as the diffusion barriers/adhesion promoters for advanced copper based metallization schemes. In this study interfacial reaction between Cu-Al alloy/SiO2 is investigated by x-ray photoelectron spectroscopy (XPS). A set of thin Cu-Al alloy films, about 30Å in thickness, are deposited on SiO2 substrates. These were directly examined by XPS. This is followed by a study of the interface formation during bias temperature stressing (BTS) of metal/dielectric interfaces in Cu/Cu-5at.%AI/SiO2 subjected to the electrical testing. Core-level spectra of silicon and aluminum obtained indicate that the reduction of silicon dioxide initiates at room temperature when the aluminum concentration in the copper alloys reaches about 5 atomic percent. The silicon diffusion into metal or vice versa is found to be suppressed during the low temperature anneal (300°C) by the Al2O3 interfacial layer. Also, a difference is present in the observed chemical states and interfacial reaction progressing between sputter and electron-beam deposited films. The films of Cu doped with Al appear to act as a suitable diffusion barrier and adhesion promoter between SiO2 and Cu.


2007 ◽  
Vol 534-536 ◽  
pp. 829-832
Author(s):  
Hai Yi Lou ◽  
Wei Lu ◽  
Lei Yang ◽  
Biao Yan

Microstructure and mechanical properties of a newly developed Zn61Al34M5 (M=Cu, Si, RE, et al.) alloy obtained by warm-compacting sintering technique were studied using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) associated with measurements of mechanical properties. The results showed that the new alloy consisted of α-phase and η-phase and have good plasticity; its hardness increased by 10%~20% and density decreased by about 16% as compared with those of the traditional cast Zn-Al alloys.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Balbir Singh ◽  
Jatinder Kumar ◽  
Sudhir Kumar

A6061/10% SiC composite has been fabricated by mechanical stir casting process. Fabricated composite has also been characterized through optical microscopy, X-ray diffraction analysis (XRD), scanning electron microscopy analysis (SEM) with energy dispersive X-ray techniques (EDX), and thermogravimetric/differential thermal analysis (TG/DTA). The composite has been experimentally investigated for its machinability usingZ-axis numerically controlled (ZNC) electrodischarge machining (EDM) process. The effects of the four process parameters, namely, current, gap voltage, pulse-on time, and pulse-off time are investigated on material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) by varying one parameter at a time approach. Optical microscopy and SEM analysis revealed the uniform distribution of SiC particles in aluminum matrix phase. XRD investigation corroborated the elemental composition of 6061 Al alloy and reinforcement particles. Thermal analysis shows stability of composite upto 650°C. The machinability characteristics, namely, MRR, TWR, and SR have been interpreted using graphical representations. The study indicates that all the machining parameters affect the machining performance of A6061/10% SiC composite. Optimum machining performance has been realized at the lower setting of current and pulse-on time and the optimum setting of pulse-off time and gap voltage.


2017 ◽  
Vol 373 ◽  
pp. 142-145 ◽  
Author(s):  
Emad A. Badawi ◽  
M.A. Abdel-Rahman ◽  
Mohammed Salah ◽  
Mohamed Abdel-Rahman

Due to the great effect of defects on the properties of the material including strength, ductility, resistivity and opacity, there are many techniques that are used in defect detecting. Positron annihilation spectroscopy (PAS), Vickers hardness, and X-ray diffraction were used to study the influence of plastic deformation on the properties of 8006 Al-alloy in this work. An increase in the positron lifetime and Vickers hardness with a bit Broadening of XRD peaks was observed with increasing the degree of deformation reflecting a large dislocation density produced by plastic deformation.


1998 ◽  
Vol 521 ◽  
Author(s):  
H. Bart-Smith ◽  
A.-F. Bastawros ◽  
D. R. Mumm ◽  
A. G. Evans ◽  
D. J. Sypeck ◽  
...  

ABSTRACTThe mechanisms of compressive deformation that occur in closed cell Al alloys have been established. This has been achieved by using x-ray computed tomography (CT) and surface strain mapping to determine the deformation modes and the cell morphologies that control the onset of yielding. The deformation is found to localize in narrow bands having width of order of a cell diameter. Outside the bands, the material remains elastic. The cells within the bands that experience large permanent strains are primarily elliptical. A group of cells work collectively to allow large localized deformation. Size does not appear to be the initiator of the deformation bands. Equiaxed cells remain elastic. The implications for manufacturing materials with superior mechanical properties are discussed. Visualization of internal deformation of a closed cell Al alloy core, as part of a sandwich panel construction, is also possible using x-ray tomography. Preliminary results for a punch indentation test are presented.


Author(s):  
L. Montoto ◽  
M. Montoto ◽  
A. Bel-Lan

INTRODUCTION.- The physical properties of rock masses are greatly influenced by their internal discontinuities, like pores and fissures. So, these need to be measured as a basis for interpretation. To avoid the basic difficulties of measurement under optical microscopy and analogic image systems, the authors use S.E.M. and multiband digital image processing. In S.E.M., analog signal processing has been used to further image enhancement (1), but automatic information extraction can be achieved by simple digital processing of S.E.M. images (2). The use of multiband image would overcome difficulties such as artifacts introduced by the relative positions of sample and detector or the typicals encountered in optical microscopy.DIGITAL IMAGE PROCESSING.- The studied rock specimens were in the form of flat deformation-free surfaces observed under a Phillips SEM model 500. The SEM detector output signal was recorded in picture form in b&w negatives and digitized using a Perkin Elmer 1010 MP flat microdensitometer.


Author(s):  
John A. Hunt ◽  
Richard D. Leapman ◽  
David B. Williams

Interactive MASI involves controlling the raster of a STEM or SEM probe to areas predefined byan integration mask which is formed by image processing, drawing or selecting regions manually. EELS, x-ray, or other spectra are then acquired while the probe is scanning over the areas defined by the integration mask. The technique has several advantages: (1) Low-dose spectra can be acquired by averaging the dose over a great many similar features. (2) MASI can eliminate the risks of spatial under- or over-sampling of multiple, complicated, and irregularly shaped objects. (3) MASI is an extremely rapid and convenient way to record spectra for routine analysis. The technique is performed as follows:Acquire reference imageOptionally blank beam for beam-sensitive specimensUse image processor to select integration mask from reference imageCalculate scanning path for probeUnblank probe (if blanked)Correct for specimen drift since reference image acquisition


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