scholarly journals Effect of Solidification Rate and Rare Earth Metal Addition on the Microstructural Characteristics and Porosity Formation in A356 Alloy

2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
M. G. Mahmoud ◽  
A. M. Samuel ◽  
H. W. Doty ◽  
S. Valtierra ◽  
F. H. Samuel
Keyword(s):  
Rare Earth ◽  
Solidification Rate ◽  
A356 Alloy ◽  
Earth Metal ◽  
Atomic Radius ◽  
Shrinkage Porosity ◽  
Minor Effect ◽  
Porosity Formation ◽  
Agent Interaction ◽  
Eutectic Si

The present study was performed on A356 alloy with the main aim of investigating the effects of La and Ce additions to 356 alloys (with and without 100 ppm Sr) on the microstructure and porosity formation in these alloys. Measured amounts of La, Ce, and Sr were added to the molten alloy. The results showed that, in the absence of Sr, addition of La and Ce leads to an increase in the nucleation temperature of the α-Al dendritic network with a decrease in the temperature of the eutectic Si precipitation, resulting in increasing the freezing range. Addition of 100 ppm Sr results in neutralizing these effects. The presence of La or Ce in the casting has a minor effect on eutectic Si modification, in spite of the observed depression in the eutectic temperature. It should be noted that Ce is more effective than La as an alternate modifying agent. According to the atomic radius ratio, rLa/rSi is 1.604 and rCe/rSi is 1.559, theoretically, which shows that Ce is relatively more effective than La. The present findings confirm that Sr is the most dominating modification agent. Interaction between rare earth (RE) metals and Sr would reduce the effectiveness of Sr. Although modification with Sr causes the formation of shrinkage porosity, it also reacts with RE-rich intermetallics, resulting in their fragmentation.

Effect of Rare Earth Metals on Porosity Formation in A356 Alloy

2017 ◽  
Vol 12 (2) ◽  
pp. 251-265 ◽  
Author(s):  
M. G. Mahmoud ◽  
E. M. Elgallad ◽  
M. F. Ibrahim ◽  
F. H. Samuel
Keyword(s):  
Rare Earth ◽  
Rare Earth Metals ◽  
A356 Alloy ◽  
Porosity Formation

scholarly journals How Slight Solidification Rate Variations within Cast Plate Affect Mechanical Response: A Study on As-Cast A356 Alloy with Cu Additions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Maria Teresa Di Giovanni ◽  
Emanuela Cerri ◽  
Takeshi Saito ◽  
Shahid Akhtar ◽  
Petter Åsholt ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Eutectic Silicon ◽  
Solidification Rate ◽  
Particle Surface ◽  
A356 Alloy ◽  
Equivalent Diameter ◽  
Particle Surface Area ◽  
Eutectic Si ◽  
Backscattered Electron ◽  
Cast Plate

The present work investigates a narrow range of secondary dendrite arm spacing (SDAS), in an as-cast A356 alloy with and without copper (Cu) additions. Cu was added to the base A356 alloy melt to reach the target concentration of 0.5 and 1 wt.%. Samples were selected from 3 different positions within the cast plate, offering 30, 35, and 40 μm SDAS variants. Tensile curves revealed a strong influence between the specimen cutting position and strength, with a pronounced effect in the Cu-containing alloys. Hardness measurements did not confirm the tensile response; hence, to understand the phenomenon, microstructural features have been investigated in detail. Eutectic silicon (Si) particle equivalent diameter (ED) size decreased from the top (T) to the bottom (B) position of the cast. Eutectic Si particle surface area (A%) was found to be denser at the B as compared to the T and simultaneously in the Cu-containing alloy as compared to the Cu-free reference alloy. Backscattered electron (BSE) images were employed to investigate the nature of the Cu-rich intermetallic phases. In conclusion, electrical conductivity measurements were performed to confirm the trends observed.

Phase selectivity and tunable photophysical nature of rare earth metal–organic frameworks of EuxY1−x-PTC (H3PTC = 2,4,6-pyridine tricarboxylic acid; x = 0–1)

2020 ◽  
Vol 49 (42) ◽  
pp. 14985-14994
Author(s):  
Xu-Sheng Gao ◽  
Mei-Juan Ding ◽  
Jin Zhang ◽  
Li-Duo Zhao ◽  
Xiao-Ming Ren
Keyword(s):  
Rare Earth ◽  
Solid Solutions ◽  
Rare Earth Metal ◽  
Metal Organic Frameworks ◽  
Earth Metal ◽  
Tricarboxylic Acid ◽  
Excitation Wavelength ◽  
Metal Organic ◽  
Phase Selectivity

All solid solutions (EuxY1−x-PTC, x = 0.013–0.82) are isomorphic to Eu-PTC, but different from Y-PTC, and show phase selectivity as well as excitation wavelength dependent emission.

scholarly journals Experimental Investigation of WE54 magnesium rare earth metal alloys by ageing treatment

2021 ◽  
Vol 1104 (1) ◽  
pp. 012025
Author(s):  
Sachendra ◽  
Shailesh Kumar Singh ◽  
Ujjwal ◽  
Satyajeet Kumar ◽  
Kuldeep Singh
Keyword(s):  
Experimental Investigation ◽  
Rare Earth ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Metal Alloys ◽  
Ageing Treatment

scholarly journals High-pressure synthesis of REB5O8(OH)2 (RE = Ho, Er, Tm)

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Michael Zoller ◽  
Hubert Huppertz
Keyword(s):  
High Pressure ◽  
Rare Earth ◽  
Ir Spectroscopy ◽  
Earth Metal ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Solution ◽  
Pressure Synthesis ◽  
The Rare Earth

AbstractThe rare earth oxoborates REB5O8(OH)2 (RE = Ho, Er, Tm) were synthesized in a Walker-type multianvil apparatus at a pressure of 2.5 GPa and a temperature of 673 K. Single-crystal X-ray diffraction data provided the basis for the structure solution and refinement. The compounds crystallize in the monoclinic space group C2 (no. 5) and are composed of a layer-like structure containing dreier and sechser rings of corner sharing [BO4]5− tetrahedra. The rare earth metal cations are coordinated between two adjacent sechser rings. Further characterization was performed utilizing IR spectroscopy.

Phosphorylated-calix[4]arene double-deckers of single rare earth metal ions

2021 ◽  
Author(s):  
Marjan Hosseinzadeh ◽  
Sergio Sanz ◽  
Jan van Leusen ◽  
Natalya V Izarova ◽  
Euan K Brechin ◽  
...  
Keyword(s):  
Rare Earth ◽  
Metal Ions ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Double Decker ◽  
Organic Framework

Combination of phosphoryl and calix[4]arene moieties in the same organic framework (LPO) directs the formation of homoleptic double-decker complexes [LnIII(LPO)2](O3SCF3)3 for Ln = Tb and Dy, with the latter displaying...

Deep-ultraviolet transparent alkali metal-rare earth metal sulfate NaY(SO4)2.H2O as a nonlinear optical crystal: synthesis and characterization

CrystEngComm ◽  
2021 ◽  
Author(s):  
Chao Wu ◽  
Lin Lin ◽  
Tianhui Wu ◽  
Zhipeng Huang ◽  
Chi Zhang
Keyword(s):  
Rare Earth ◽  
Alkali Metal ◽  
Rare Earth Metal ◽  
Earth Metal ◽  
Synthesis And Characterization ◽  
Nonlinear Optical Crystal ◽  
Metal Sulfate ◽  
Deep Ultraviolet ◽  
Crystal Synthesis ◽  
Optical Crystal

A new alkali metal-rare earth metal sulfate with the formula NaY(SO4)2.H2O has been synthesized using a mild hydrothermal method. It crystallizes in the noncentrosymmetric trigonal space group P3121 (No. 152)...

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