Experimental Analysis of Seed Effect on the Directional Solidification of Sn-Pb Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 343-347
Author(s):  
Long Sun Chao ◽  
Yu Ru Chen ◽  
Fang Chun Wang
Keyword(s):  
Directional Solidification ◽  
Experimental Analysis ◽  
Casting Process ◽  
Growth Direction ◽  
Columnar Growth ◽  
Preferential Growth ◽  
Microstructure Observation ◽  
Preferential Growth Direction ◽  
Mechanical And Physical Properties ◽  
Bottom Portion

In this paper, an experiment model for the directional solidification of Lead/Tin alloy is built and the effects of different-shape seeds on the microstructures on the solidification microstructure are investigated. In a casting process, the temperature and concentration fields will affect the microstructures of materials and this influence is the key point of improving their mechanical and physical properties. It is not easy to control the morphology of solidifying microstructures. The scheme of directional solidification can make the microstructures grow along a fixed direction and it is also the base of single-crystal growth. In the experiment, a poly-grain seed with the same initial concentration of the solidifying casting is used to induce the columnar growth at the bottom portion of the casting, which could avoid the equiaxed growth due to the high undercooling or cooling rate there. In the experimental analysis, we studied the influences of different geometry seeds on the constrained growth, the preferential growth direction of dendrite, the grain size, the temperature gradient, the growth rate, the primary arm spacing and the secondary arm spacing. From the microstructure observation, the adding seed casting reduced the chill-affected and extended the directional solidification zone. This is expected to have the better or more complete structure of directional solidification. Keywords: Directional Solidification, Seed, Heat Transfer and Microstructure

Influence of Time and Temperature on Directional Growth of MoO3

2016 ◽  
Vol 869 ◽  
pp. 1001-1006
Author(s):  
Claudia Ferreira da Silva ◽  
André Lima e Silva ◽  
Francisco Xavier Nobre ◽  
Edson Cavalcanti Silva Filho ◽  
Luiz de Sousa Santos Jr. ◽  
...  
Keyword(s):  
Glacial Acetic Acid ◽  
Molybdenum Trioxide ◽  
Orthorhombic Phase ◽  
Growth Direction ◽  
X Ray Diffraction ◽  
Directional Growth ◽  
Preferential Growth ◽  
X Ray ◽  
Preferential Growth Direction ◽  
Characteristic Modes

Two-dimensional microstructures of molybdenum trioxide (MoO3) were synthesized by heptamolybdate tetrahydrate ammonium acidification, followed by calcination. A solution of the precursor compound heptamolybdate tetrahydrate ammonium acidified to pH 3,5 using glacial acetic acid followed by hydrothermal treatment for 150, 180 and 200 °C for 1, 6 and 12 hours. Then, the intermediate was calcined at 300 °C for varying time 6 and 12h to obtain MoO3. X-ray diffraction revealed that the crystals grew with crystalline structure corresponding to the orthorhombic phase of MoO3 (a-MoO3) as major phase, with a preferential growth direction along the planes (0K0). Raman spectroscopy and IR confirmed the formation of the characteristic modes of molybdenum trioxide for stage found. With Scanning Electron Microscopy (SEM) was possible to observe the formation of nanoplates.

ANISOTROPIC GOLD NANOCRYSTALS: SYNTHESIS AND CHARACTERIZATION

2010 ◽  
Vol 24 (06n07) ◽  
pp. 757-761 ◽  
Author(s):  
R. STIUFIUC ◽  
F. TODERAS ◽  
M. IOSIN ◽  
G. STIUFIUC
Keyword(s):  
Growth Direction ◽  
Preferential Growth ◽  
Gold Nanocrystals ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Preferential Growth Direction ◽  
Phase Images ◽  
Means Of Transmission

In this letter we report on successful preparation and characterization of anisotropic gold nanocrystals bio-synthesized by reduction of aqueous chloroaurate ions in pelargonium plant extract. The nanocrystals have been characterized by means of Transmission Electron Microscopy (TEM), UV-VIS absorption spectroscopy and tapping mode atomic force microscopy (TM-AFM). Using these investigation techniques, the successful formation of anisotropic single nanocrystals with the preferential growth direction along the gold (111) plane has been confirmed. The high detail phase images could give us an explanation concerning the growth mechanism of the nanocrystals.

OPTICAL PROPERTIES OF Ge NANOWIRES GROWN ON SILICON (100) AND (111) SUBSTRATES

2004 ◽  
Vol 832 ◽  
Author(s):  
V. Sharma ◽  
B. V. Kamenev ◽  
L. Tsybeskov ◽  
T. I. Kamins
Keyword(s):  
Vapor Deposition ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Silicon Substrates ◽  
Si Substrate ◽  
Vapor Liquid Solid ◽  
Preferential Growth ◽  
Intensity Dependence ◽  
Si Substrates ◽  
Preferential Growth Direction

ABSTRACTIn this paper, we report Raman Scattering (RS) and photoluminescence (PL) measurements of Ge nanowires (NWs) grown via vapor-liquid-solid (VLS) using chemical vapor deposition silicon substrates consisting of (100) and (111) crystallographic orientations. Ge NWs grown are ∼40 nm in diameter, approximately a micrometer in length, and a sharp narrow Raman peak at ∼300 cm−1 indicates single crystal quality. An absence of SiGe peak in the Raman spectra indicates that SiGe interdiffusion is insignificant for the NW volume. Low temperature PL-intensity-dependence spectra indicate that the observed emission originates at the Ge NW – Si substrate interface, where SiGe intermixing has been detected. This interface is formed differently for (111) and (100) oriented Si substrates due to the <111> preferential growth direction of Ge NWs.

Morphogenesis of anisotropic nanoparticles: self-templating via non-classical, fibrillar Cd2Se intermediates

2018 ◽  
Vol 54 (53) ◽  
pp. 7358-7361 ◽  
Author(s):  
Daniel Wurmbrand ◽  
Jörg Wolfram Anselm Fischer ◽  
Rose Rosenberg ◽  
Klaus Boldt
Keyword(s):  
Growth Direction ◽  
Preferential Growth ◽  
Anisotropic Nanoparticles ◽  
Preferential Growth Direction

Semiconductor nanorods nucleate via a fibrillar intermediate that is able to template its own preferential growth direction.

Mechanical properties of NiAl-Mo composites produced by specially controlled directional solidification

2012 ◽  
Vol 1516 ◽  
pp. 255-260 ◽  
Author(s):  
G. Zhang ◽  
L. Hu ◽  
W. Hu ◽  
G. Gottstein ◽  
S. Bogner ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Directional Solidification ◽  
Creep Resistance ◽  
Room Temperature ◽  
Growth Direction ◽  
Nominal Composition ◽  
Potential Candidate ◽  
In Situ Composites

ABSTRACTMo fiber reinforced NiAl in-situ composites with a nominal composition Ni-43.8Al-9.5Mo (at.%) were produced by specially controlled directional solidification (DS) using a laboratory-scale Bridgman furnace equipped with a liquid metal cooling (LMC) device. In these composites, single crystalline Mo fibers were precipitated out through eutectic reaction and aligned parallel to the growth direction of the ingot. Mechanical properties, i.e. the creep resistance at high temperatures (HT, between 900 °C and 1200 °C) and the fracture toughness at room temperature (RT) of in-situ NiAl-Mo composites, were characterized by tensile creep (along the growth direction) and flexure (four-point bending, vertical to the growth direction) tests, respectively. In the current study, a steady creep rate of 10-6s-1 at 1100 °C under an initial applied tensile stress of 150MPa was measured. The flexure tests sustained a fracture toughness of 14.5 MPa·m1/2at room temperature. Compared to binary NiAl and other NiAl alloys, these properties showed a remarkably improvement in creep resistance at HT and fracture toughness at RT that makes this composite a potential candidate material for structural application at the temperatures above 1000 °C. The mechanisms responsible for the improvement of the mechanical properties in NiAl-Mo in-situ composites were discussed based on the investigation results.

Inverse segregation during transient directional solidification of an Al–Sn alloy: Numerical and experimental analysis

2009 ◽  
Vol 115 (1) ◽  
pp. 116-121 ◽  
Author(s):  
Kleber S. Cruz ◽  
Ivaldo L. Ferreira ◽  
José E. Spinelli ◽  
Noé Cheung ◽  
Amauri Garcia
Keyword(s):  
Directional Solidification ◽  
Experimental Analysis ◽  
Inverse Segregation

Resistivity Distribution Characteristics of Metallurgical Silicon Ingot after Directional Solidification

2011 ◽  
Vol 675-677 ◽  
pp. 109-112
Author(s):  
Shu Ang Shi ◽  
Wei Dong ◽  
Shi Hai Sun ◽  
Yi Tan ◽  
Guo Bin Li ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Vertical Section ◽  
Growth Direction ◽  
Silicon Ingot ◽  
Metallurgical Silicon ◽  
High Impurity ◽  
Polarity Transition ◽  
High Impurity Concentration ◽  
Solid Liquid Interface ◽  
Solid Liquid

The distribution of resistivity, impurity and polarity in multicrystalline silicon ingot prepared by directional solidification method was detected. The effect of impurity distribution on resistivity was also researched. The results show that the shapes of equivalence line of resistivity in the cross section and vertical section of the silicon ingot depend on the solid-liquid interface. The resistivity in the vertical section increases with the increasing of solidified height at the beginning of solidification and reaches to maximum at the polarity transition point, then decreases rapidly with the increasing of solidified height and tends to zero on the top of the ingot because of the high impurity concentration. Study proves that the variation of resistivity in the vertical section is mainly relevant to the concentration distribution of the impurities such as Al, B and P in the growth direction.

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