Characterization of the Corrosion Behavior of Hot Pressed Nanocomposites Al-SiC Powder

2009 ◽  
Vol 83-86 ◽  
pp. 429-438 ◽  
Author(s):  
Taha Rostamzadeh ◽  
H. Shahverdi ◽  
A. Shanaghi ◽  
T. Shahrabi

The object of the present work is the characterization of the corrosion behavior of Al-5%SiC nanocomposites prepared by mechanical alloying and the hot pressing method. Al/SiC metal matrix composite (MMCp) powder with volume fraction of 5% SiC was synthesized by high-energy milling of the blended micro component powder. The mechanically mixed nanocomposite powder was consolidated into bulk compacts using hot pressing at 1 GPa pressure for thirty seconds at three different temperatures of 440, 480 and 520°C. The microstructure was investigated by Secondary electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The corrosion behavior of the coating was evaluated using electrochemical techniques such as potansiodynamic polarization and EIS. It was found that the corrosion resistance of Al-5%SiC nanocomposite when hot pressed at 480°C, in 3.5% NaCl solution was higher than pure Al and Al-SiC nanocomposite that had been hot pressed at other temperatures.

2007 ◽  
Vol 539-543 ◽  
pp. 2353-2358 ◽  
Author(s):  
Ulrich Lienert ◽  
Jonathan Almer ◽  
Bo Jakobsen ◽  
Wolfgang Pantleon ◽  
Henning Friis Poulsen ◽  
...  

The implementation of 3-Dimensional X-Ray Diffraction (3DXRD) Microscopy at the Advanced Photon Source is described. The technique enables the non-destructive structural characterization of polycrystalline bulk materials and is therefore suitable for in situ studies during thermo-mechanical processing. High energy synchrotron radiation and area detectors are employed. First, a forward modeling approach for the reconstruction of grain boundaries from high resolution diffraction images is described. Second, a high resolution reciprocal space mapping technique of individual grains is presented.


2015 ◽  
Vol 75 (7) ◽  
Author(s):  
Amir Arifin ◽  
Abu Bakar Sulong ◽  
Norhamidi Muhamad ◽  
Junaidi Syarif

Hydroxyapatite (HA) has been widely used in biomedical applications due to its excellent biocompatibility. However, Hydroxyapatite possesses poor mechanical properties and only tolerate limited loads for implants. Titanium is well-known materials applied in implant that has advantage in mechanical properties but poor in biocompatibility. The combination of the Titanium alloy and HA is expected to produce bio-implants with good in term of mechanical properties and biocompatabilty. In this work, interaction and mechanical properties of HA/Ti6Al4V was analyzed. The physical and mechanical properties of HA/Ti6Al4V composite powder obtained from compaction (powder metallurgy) of 60 wt.% Ti6Al4V and 40 wt.% HA and sintering at different temperatures in air were investigated in this study. Interactions of the mixed powders were investigated using X-ray diffraction. The hardness and density of the HA/Ti6Al4V composites were also measured. Based on the results of XRD analysis, the oxidation of Ti began at 700 °C. At 1000 °C, two phases were formed (i.e., TiO2 and CaTiO3). The results showed that the hardness HA/Ti6Al4V composites increased by 221.6% with increasing sintering temperature from 700oC to 1000oC. In contrast, the density of the composites decreased by 1.9% with increasing sintering temperature. 


1995 ◽  
Vol 395 ◽  
Author(s):  
S. A. Ustin ◽  
L. Lauhon ◽  
K. A. Brown ◽  
D. Q. Hu ◽  
W. Ho

ABSTRACTHighly oriented aluminum nitride (0001) films have been grown on Si(001) and Si (111) substrates at temperatures between 550° C and 775° C with dual supersonic molecular beam sources. Triethylaluminum (TEA;[(C2H5)3Al]) and ammonia (NH3) were used as precursors. Hydrogen, helium, and nitrogen were used as seeding gases for the precursors, providing a wide range of possible kinetic energies for the supersonic beams due to the disparate masses of the seed gases. Growth rates of AIN were found to depend strongly on the substrate orientation and the kinetic energy of the incident precursor; a significant increase in growth rate is seen when seeding in hydrogen or helium as opposed to nitrogen. Growth rates were 2–3 times greater on Si(001) than on Si(111). Structural characterization of the films was done by reflection high energy electron diffraction (RHEED) and x-ray diffraction (XRD). X-ray rocking curve (XRC) full-width half-maxima (FWHM) were seen as small as 2.5°. Rutherford back scattering (RBS) was used to determine the thickness of the films and their chemical composition. Films were shown to be nitrogen rich, deviating from perfect stoichiometry by 10%–20%. Surface analysis was performed by Auger electron spectroscopy (AES).


Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5188
Author(s):  
Iris Raffeis ◽  
Frank Adjei-Kyeremeh ◽  
Uwe Vroomen ◽  
Silvia Richter ◽  
Andreas Bührig-Polaczek

Al-Cu-Li alloys are famous for their high strength, ductility and weight-saving properties, and have for many years been the aerospace alloy of choice. Depending on the alloy composition, this multi-phase system may give rise to several phases, including the major strengthening T1 (Al2CuLi) phase. Microstructure investigations have extensively been reported for conventionally processed alloys with little focus on their Additive Manufacturing (AM) characterised microstructures. In this work, the Laser Powder Bed Fusion (LPBF) built microstructures of an AA2099 Al-Cu-Li alloy are characterised in the as-built (no preheating) and preheat-treated (320 °C, 500 °C) conditions using various analytical techniques, including Synchrotron High-Energy X-ray Diffraction (S-HEXRD). The observed dislocations in the AM as-built condition with no detected T1 precipitates confirm the conventional view of the difficulty of T1 to nucleate on dislocations without appropriate heat treatments. Two main phases, T1 (Al2CuLi) and TB (Al7.5Cu4Li), were detected using S-HEXRD at both preheat-treated temperatures. Higher volume fraction of T1 measured in the 500 °C (75.2 HV0.1) sample resulted in a higher microhardness compared to the 320 °C (58.7 HV0.1) sample. Higher TB volume fraction measured in the 320 °C sample had a minimal strength effect.


Cerâmica ◽  
2007 ◽  
Vol 53 (328) ◽  
pp. 422-447
Author(s):  
F. C. D. Lemos ◽  
D. M. A. Melo ◽  
P. S. de Lima ◽  
C. A. Paskocimas ◽  
E. Longo ◽  
...  

Rare earth modified lead titanate powders Pb1-xRExTiO3 (REPT), x = 0.01, 0.05, 0.07 and RE = Yb, Y, were prepared by the Pechini method. The materials were calcined under flowing oxygen at different temperatures from 300 to 700 ºC. Nanostructured REPT were investigated using X-ray diffraction, scanning electron microscopy and surface area analysis (BET). The results suggest that the modifier cation incorporated into the system has notable influence in the microstructure and a notable decrease in the crystallite sizes.


2007 ◽  
Vol 342-343 ◽  
pp. 213-216 ◽  
Author(s):  
Xiao Ying Lü ◽  
Yong Bin Fan ◽  
Dachun Gu ◽  
Wei Cui

The purpose of this study is to find out an effective method to prepare natural hydroxyapatite (HA) from biological source, i.e., pig bones, pig teeth, and extracted human teeth. For the preparation of natural HA a calcining method with different temperatures was used, in combination with the thermal gravimetric analysis (TGA). Three analysis methods, i.e., Fourier transform infrared spectroscope (FTIR), X-ray diffraction (XRD), and inductively coupled plasma (ICP) have been used to investigate the characteristics of the prepared materials. The spectrum of the prepared material, obtained by means of FTIR and XRD, are consistent with the standard FTIR spectrum and JCPDS index of XRD of hydroxyapitite. It confirms that the material prepared is hydroxyapitite indeed. The natural HA obtained by calcining at 850°C shows a desired quality.


2015 ◽  
Vol 60 (2) ◽  
pp. 1523-1527 ◽  
Author(s):  
M. Suśniak ◽  
J. Karwan-Baczewska ◽  
J. Dutkiewicz ◽  
M. Actis Grande ◽  
M. Rosso

Abstract The present work investigates the possibility of using powder metallurgy processing for producing a metal matrix composite. Materials were prepared from AlSi5Cu2 chips with reinforcement of 10, 15, 20 wt. % silicon carbide. Aluminum alloy chips were milled with SiC powder in a high-energy ball mill by 40 hours. Mechanical alloying process lead to obtain an uniform distribution of hard SiC particles in the metallic matrix and refine the grain size. The consolidation of composite powders was performed by vacuum hot pressing at 450°C, under pressure of 600 MPa by 10 min. The results shows that the addition of SiC particles has a substantial influence on the microstructure and mechanical properties of composite powder as well as consolidated material. Hot pressing is an effective consolidation method which leads to obtain dense AlSi5Cu2/SiC composite with homogeneous structure and advanced mechanical properties.


2011 ◽  
Vol 412 ◽  
pp. 263-266
Author(s):  
Hong Wei Zhang ◽  
Li Li Zhang ◽  
Feng Rui Zhai ◽  
Jia Jin Tian ◽  
Can Bang Zhang

The higher mechanical strength of Al87Ce3Ni8.5Mn1.5 nanophase amorphous composites has been obtained with two methods. The first nanophase amorphous composites are directly produced by the single roller spin quenching technology. The method taken for the second nanophase amorphous composites is at first to obtain amorphous single-phase alloy, followed by annealed at different temperatures .The formative condition, the microstructure, the particle size, the volume fraction of α-Al phase and microhardness of nanophase amorphous composites etc have been investigated and compared by X-ray diffraction (XRD) and transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The microstructure of composites produced by the second method is higher than the former, the fabricated material structure of the system is more uniform and the process is easier to control.


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