scholarly journals Effect of Rare Earth Metals, Sr, and Ti Addition on the Microstructural Characterization of A413.1 Alloy

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
M. G. Mahmoud ◽  
A. M. Samuel ◽  
H. W. Doty ◽  
S. Valtierra ◽  
F. H. Samuel
Keyword(s):  
Rare Earth ◽  
Eutectic Temperature ◽  
Rare Earth Metals ◽  
Microstructural Characterization ◽  
Second Phase ◽  
White Phase ◽  
Eutectic Si ◽  
Ti Addition ◽  
Grey Phase

The present work was performed on A413.1 alloy containing 0.2–1.5 wt% rare earth metals (lanthanum or cerium), 0.05–0.15% Ti, and 0–0.02 wt% Sr. These elements were either added individually or combined. Thermal analysis, image analysis, and electron probe microanalysis were the main techniques employed in the present study. The results show that the use of the depression in the eutectic temperature as a function of alloy modification cannot be applied in the case when the alloy is treated with rare earth metals. Increasing the concentration of RE increases the solidification zone especially in Sr-modified alloys leading to poor feeding ability. This observation is more prominent in the case of Ce addition. Depending upon the amount of added Ti, two RE based intermetallics can be formed: (i) a white phase, mainly platelet-like (approximately 2.5 μm thick), that is rich in RE, Si, Cu, and Al and (ii) a second phase made up of mainly grey sludge particles (star-like) branching in different directions. The grey phase is rich in Ti with some RE (almost 20% of that in the white phase) with traces of Si and Cu. There is a strong interaction between RE and Sr leading to a reduction in the efficiency of Sr as a eutectic Si modifier causing particle demodification.

scholarly journals Microstructural Characterization of Beryllium Treated Al-Si Alloys

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
M. F. Ibrahim ◽  
S. A. Alkahtani ◽  
Kh. A. Abuhasel ◽  
F. H. Samuel
Keyword(s):  
Mechanical Properties ◽  
Fine Particles ◽  
Eutectic Temperature ◽  
Microstructural Characterization ◽  
Noticeable Effect ◽  
Thermal Analysis Technique ◽  
Analysis Technique ◽  
Eutectic Si ◽  
Harmful Effects

The present study was carried out on B356 and B357 alloys using the thermal analysis technique. Metallographic samples prepared from these castings were examined using optical microscopy and FESEM. Results revealed that beryllium causes partial modification of the eutectic Si, similar to that reported for magnesium additions. Addition of 0.8 wt.% Mg reduces the eutectic temperature by ~10°C. During solidification of alloys containing high levels of Fe and Mg, but no Sr, formation of a Be-Fe phase was detected at 611°C, close to that ofα-Al. The Be-Fe phase precipitates in script-like form at or close to theβ-Al5SiFe platelets. A new reaction, composed of fine particles of Si andπ-Fe phase, was observed to occur near the end of solidification in high Mg-, high Fe-, and Be-containing alloys. The amount of this reaction decreased with the addition of Sr. Occasionally, Be-containing phase particles were observed as part of the reaction. Addition of Be has a noticeable effect on decreasing theβ-Al5FeSi platelet length; this effect may be enhanced by addition of Sr. Beryllium addition also results in precipitation of theβ-Al5FeSi phase in nodular form, which lowers its harmful effects on the alloy mechanical properties.

scholarly journals Effects of La and Ce Addition on the Modification of Al-Si Based Alloys

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Emad M. Elgallad ◽  
Herbert W. Doty ◽  
Saleh A. Alkahtani ◽  
Fawzy H. Samuel
Keyword(s):  
Rare Earth ◽  
Standard Deviation ◽  
Melting Temperature ◽  
Eutectic Temperature ◽  
Rare Earth Metals ◽  
Rare Earth Intermetallics ◽  
High Affinity ◽  
Eutectic Si ◽  
Microstructural Examination

This study focuses on the effects of the addition of rare earth metals (mainly lanthanum and cerium) on the eutectic Si characteristics in Al-Si based alloys. Based on the solidification curves and microstructural examination of the corresponding alloys, it was found that addition of La or Ce increases the alloy melting temperature and the Al-Si eutectic temperature, with an Al-Si recalescence of 2-3°C, and the appearance of post-α-Al peaks attributed to precipitation of rare earth intermetallics. Addition of La or Ce to Al-(7–13)% Si causes only partial modification of the eutectic Si particles. Lanthanum has a high affinity to react with Sr, which weakens the modification efficiency of the latter. Cerium, however, has a high affinity for Ti, forming a large amount of sludge. Due to the large difference in the length of the eutectic Si particles in the same sample, the normal use of standard deviation in this case is meaningless.

Microstructural characterization of a cast RENi5-based alloy

1993 ◽  
Vol 51 ◽  
pp. 1176-1177
Author(s):  
G. M. Micha ◽  
L. Zhang
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Microstructural Characterization ◽  
Binary Compound ◽  
Nickel Metal ◽  
Cast Material ◽  
Nickel Metal Hydride ◽  
Transmission Electron ◽  
Cast Condition

RENi5 (RE: rare earth) based alloys have been extensively evaluated for use as an electrode material for nickel-metal hydride batteries. A variety of alloys have been developed from the prototype intermetallic compound LaNi5. The use of mischmetal as a source of rare earth combined with transition metal and Al substitutions for Ni has caused the evolution of the alloy from a binary compound to one containing eight or more elements. This study evaluated the microstructural features of a complex commercial RENi5 based alloy using scanning and transmission electron microscopy.The alloy was evaluated in the as-cast condition. Its chemistry in at. pct. determined by bulk techniques was 12.1 La, 3.2 Ce, 1.5 Pr, 4.9 Nd, 50.2 Ni, 10.4 Co, 5.3 Mn and 2.0 Al. The as-cast material was of low strength, very brittle and contained a multitude of internal cracks. TEM foils could only be prepared by first embedding pieces of the alloy in epoxy.

Nanoscale Three-Dimensional Microstructural Characterization of an Sn-Rich Solder Alloy Using High-Resolution Transmission X-Ray Microscopy (TXM)

2016 ◽  
Vol 22 (4) ◽  
pp. 808-813 ◽  
Author(s):  
Chandrashekara S. Kaira ◽  
Carl R. Mayer ◽  
V. De Andrade ◽  
Francesco De Carlo ◽  
Nikhilesh Chawla
Keyword(s):  
Fresnel Zone ◽  
Three Dimensional ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Full Field ◽  
X Ray ◽  
Second Phase Particles ◽  
Rich Alloy ◽  
Nanoscale Features

AbstractThree-dimensional (3D) nondestructive microstructural characterization was performed using full-field transmission X-ray microscopy on an Sn-rich alloy, at a spatial resolution of 60 nm. This study highlights the use of synchrotron radiation along with Fresnel zone plate optics to perform absorption contrast tomography for analyzing nanoscale features of fine second phase particles distributed in the tin matrix, which are representative of the bulk microstructure. The 3D reconstruction was also used to quantify microstructural details of the analyzed volume.

The Effect of Temperature and Time on the Formation of a Reaction Interlayer During Aluminizing of a Carbon Steel

2009 ◽  
Vol 1242 ◽  
Author(s):  
R. Torres ◽  
V.H. López ◽  
J.P. Arredondo ◽  
R. García ◽  
J.A. Verduzco ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Kinetic Study ◽  
Microstructural Characterization ◽  
Tube Furnace ◽  
Effect Of Temperature ◽  
Second Phase ◽  
Growth Profiles ◽  
Isothermal Growth ◽  
Steel Substrates

ABSTRACTA kinetic study was performed on the growth of a reaction interlayer between molten Al and carbon steel substrates at temperatures between 665 to 820°C by holding Al/flux/steel assemblies, in a tube furnace, at temperature for times up to 120 min. An Ar atmosphere and a K-Al-F based flux were used to enable spreading of molten Al on the steel substrates. Chemical and microstructural characterization of the samples revealed that the interlayer is composed of FeAl3 and Fe2Al5, being the second phase significantly thicker. The Fe2Al5 phase grows toward the steel with a tongue like morphology. Isothermal growth profiles of the reaction interlayer followed a parabolic behavior, meaning that at the beginning the reaction is very rapid and once that a continuous interlayer is formed the growth of the interlayer is controlled by interdifussion of species across the interlayer.

Synthesis and characterization of phenanthren-o-iminoquinone complexes of rare earth metals

2010 ◽  
Vol 695 (25-26) ◽  
pp. 2774-2780 ◽  
Author(s):  
Mikhail N. Bochkarev ◽  
Anatoly A. Fagin ◽  
Nikolai O. Druzhkov ◽  
Vladimir K. Cherkasov ◽  
Marina A. Katkova ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
Synthesis And Characterization ◽  
Complexes Of Rare Earth

Microstructural characterization of a die-cast magnesium-rare earth alloy

2001 ◽  
Vol 45 (12) ◽  
pp. 1423-1429 ◽  
Author(s):  
I.P Moreno ◽  
T.K Nandy ◽  
J.W Jones ◽  
J.E Allison ◽  
T.M Pollock
Keyword(s):  
Rare Earth ◽  
Microstructural Characterization ◽  
Rare Earth Alloy ◽  
Die Cast ◽  
Cast Magnesium

Synthesis and structural characterization of amido scorpionate rare earth metals complexes

2014 ◽  
Vol 43 (25) ◽  
pp. 9586 ◽  
Author(s):  
Isabel Márquez-Segovia ◽  
Agustín Lara-Sánchez ◽  
Antonio Otero ◽  
Juan Fernández-Baeza ◽  
José Antonio Castro-Osma ◽  
...  
Keyword(s):  
Rare Earth ◽  
Structural Characterization ◽  
Rare Earth Metals

Microstructural Characterization of Dual and Multiphase Steels Applied to Automotive Industry

2014 ◽  
Vol 775-776 ◽  
pp. 146-150 ◽  
Author(s):  
Cristina Sayuri Fukugauchi ◽  
Antonio dos Reis Faria Neto ◽  
Rosinei Batista Ribeiro ◽  
Marcelo dos Santos Pereira
Keyword(s):  
Mechanical Properties ◽  
Microstructural Characterization ◽  
Tensile Tests ◽  
Ferrite Matrix ◽  
Microstructure Characterization ◽  
Second Phase ◽  
Dual Phase ◽  
Dual Phase Steels ◽  
Trip Steels

TRIP (Transformation Induced Plasticity) and DP (Dual-Phase) steels are written in a new series of steels which present excellent mechanical properties. As for microstructure aspect, TRIP steels consist on a ferrite matrix with a second phase dispersion of other constituents, such as bainite, martensite and retained austenite, while dual-phase steels consist on martensite dispersion in a ferrite matrix. In order to identify the different microconstituents present in these materials, microstructure characterization techniques by optical microscopy (using different etchants: LePera, Heat-Tinting and Nital) and scanning electron microscopy were carried out. This being so, microstructures were correlated with mechanical properties of materials, determined by means of tensile tests. It is concluded that steels assisted by TRIP effect have a strength and elongation relation higher than the dual-phase one. With microstructure characterization, it was observed phases present in these materials microstructure.

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