Effect of Silicon on the Cast Macrostructure of Fe-Si Alloys

2012 ◽  
Vol 1372 ◽  
Author(s):  
H. J. A. García ◽  
M. H. Cruz ◽  
A. A. Balandra ◽  
F. G. González ◽  
Y Houbaert
Keyword(s):  
Silicon Content ◽  
Induction Furnace ◽  
Dendritic Structure ◽  
Inert Atmosphere ◽  
Freezing Range ◽  
Electric Induction ◽  
Columnar Grains ◽  
Cast Alloys ◽  
Equiaxed Grains ◽  
Central Slice

ABSTRACTIn this work was studied the effect of silicon content from 0.5 to 3 wt.% Si on the macrostructure of casting ingots. Fe-Si alloys with low contents of impurities were produced in electric induction furnace under inert atmosphere. Castings of 12.5 cm thick, 25 cm long and 30 cm high were obtained of each alloy poured into metallic mould. The ingots obtained were sectioned in slices of 12 cm wide, 25 cm high and 2 cm thick, the central slice of each ingot was prepared metallographically to reveal the macrostructure of the six cast alloys. The results indicate that alloys with low silicon levels (0.5 and 1.0% Si) and with small solidification intervals have relatively fine equiaxed grains, while alloys with higher silicon content and a higher solidification intervals present predominantly columnar grains. These macrostructures are not the usually structures linked to short and long freezing range. Another important result is the absence of dendritic structure usually present in cast alloys.

Formation of Grain Structures of Thermal Sprayed Nickel Coatings and the Coating Properties

2005 ◽  
Vol 502 ◽  
pp. 517-0
Author(s):  
Kenji Murakami
Keyword(s):  
Steel Substrate ◽  
Nickel Coatings ◽  
Grain Structures ◽  
Heat Treated ◽  
Columnar Grains ◽  
Different Temperatures ◽  
Plasma Sprayed ◽  
Equiaxed Grains ◽  
Sprayed Coatings ◽  
Lamellar Interfaces

Pure nickel powder was low pressure plasma sprayed onto a steel substrate held at different temperatures during spraying. The as-sprayed coatings consist of columnar grains whose axes are nearly perpendicular to the lamellae composing the coatings. As the coating temperature becomes higher, the length of the columnar grains increases and is longer than the thickness of the lamellae, indicating the growth of the grains across the lamellar interfaces during spraying. On the other hand, the coatings that were heat treated after spraying consist of coarse equiaxed grains. The coatings that experienced high temperatures during spraying or the heat treated coatings have large porosity and contain large globular pores. The hardness, apparent density and the tensile strength of the coating itself were the highest for the coating prepared at a low temperature and became low on heat treatment. The thermal conductivity in the direction perpendicular to the coating was the largest for the coating that consisted of long columnar grains.

scholarly journals Corrosion Resistance of 2060 Aluminum–Lithium Alloy LBW Welds Filled with Al-5.6Cu Wire

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1988 ◽  
Author(s):  
Fencheng Liu ◽  
Xiaoguang Wang ◽  
Baosheng Zhou ◽  
Chunping Huang ◽  
Feiyue Lyu
Keyword(s):  
Intergranular Corrosion ◽  
Laser Beam Welding ◽  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Equiaxed Dendrite ◽  
Al2cu Phase ◽  
Immersion Corrosion ◽  
Aluminum Lithium ◽  
Columnar Grains ◽  
Equiaxed Grains

Alloy sheets of type 2060 aluminum–lithium were welded by laser beam welding (LBW) filled with ER2319 Al-5.6Cu wire. Microstructural observations showed the uneven distribution of columnar grains, equiaxed grains and equiaxed dendrite grains in the weld. The θ′(Al2Cu) phase and other phases precipitated in the weld. The θ′(Al2Cu) phase centrally distributed at the grain boundaries. During the immersion corrosion, the pitting corrosion first occurred and then gradually expanded and transformed to intergranular corrosion and exfoliation corrosion. The electrochemical corrosion test showed a higher corrosion tendency of the base metal and heat-affected zone for the lower corrosion potential, but the corrosion current density of the weld was relatively larger. The segregation of Cu, Mg and other elements at the grain boundary aggravated the occurrence of intergranular corrosion.

scholarly journals Effect of Zn Content on the Microstructure and Mechanical Properties of Mg–Al–Sn–Mn Alloys

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3102
Author(s):  
Tianshuo Zhao ◽  
Yaobo Hu ◽  
Fusheng Pan ◽  
Bing He ◽  
Maosheng Guan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Dendritic Structure ◽  
Second Phase ◽  
Microstructure And Mechanical Properties ◽  
Zn Content ◽  
Dislocation Movement ◽  
Cast Alloys ◽  
Complete Recrystallization ◽  
Second Phases

High performance Mg–6Al–3Sn–0.25Mn–xZn alloys (x = 0, 0.5, 1.0, 1.5, and 2.0 wt %) without rare earth were designed. The effects of different Zn contents on the microstructure and mechanical properties were systematically investigated. The addition of Zn obviously refines the as-cast alloys dendritic structure because of the increase in the number in the second phase. For the as-extruded alloys, an appropriate amount of Zn promotes complete recrystallization, thus increasing the grain size. As the Zn content increases, the texture gradually evolves into a typical strong basal texture, which means that the basal slip is difficult to initiate. Meanwhile, the addition of Zn promotes the precipitation of small-sized second phases, which can hinder the dislocation movement. The combination of texture strengthening and precipitation strengthening is the main reason for the improvement of alloys’ strength.

A Novel Method to Fabricate Silver Chloride Films

2011 ◽  
Vol 117-119 ◽  
pp. 652-655
Author(s):  
Hui Chung Hsueh ◽  
Zue Chin Chang ◽  
Chang Ching You ◽  
C. B. Lin
Keyword(s):  
Aqueous Solution ◽  
Sodium Chloride ◽  
Cross Section ◽  
Silver Chloride ◽  
Bottom Surface ◽  
Heterogeneous Precipitation ◽  
Columnar Grains ◽  
Novel Method ◽  
Equiaxed Grains ◽  
Chloride Film

Abstract: This investigation develops a novel method for fabricating silver chloride films by the heterogeneous precipitation of sodium chloride from aqueous solution and supersaturated solid-state silver nitrate out of aqueous solution. The morphology of the bottom surface of the silver chloride film thus obtained comprises numerous porous stick structures. The top surface comprises equiaxed grains, and columnar grains are observed in the cross-section.

scholarly journals Dendritic Structure Analysis of CMSX-4 Cored Turbine Blades Roots

2016 ◽  
Vol 61 (2) ◽  
pp. 1129-1134 ◽  
Author(s):  
J. Krawczyk
Keyword(s):  
Single Crystal ◽  
Cross Sections ◽  
Induction Furnace ◽  
Turbine Blades ◽  
Dendritic Structure ◽  
Root Structure ◽  
Sem Images ◽  
X Ray ◽  
Nickel Based Superalloy

Abstract The microstructure of as-cast cored turbine blades roots, made of the single-crystal CMSX-4 nickel-based superalloy was investigated. Analysed blades were obtained by directional solidification technique in the industrial ALD Bridgman induction furnace. The investigations of the microstructure of blades roots were performed using SEM and X-ray techniques including diffraction topography with the use of Auleytner method. Characteristic shapes of dendrites with various arrangement were observed on the SEM images taken from the cross-sections, made transversely to the main blades axis. The differences in quality of the structure in particular areas of blades roots were revealed. Based on the results, the influence of cooling bores on blades root structure was analysed and the changes in the distribution and geometry of cooling bores were proposed.

Microstructure Characterization of AZ31B Mg Alloy Welds Processed by Nd:YAG Laser Welding

2017 ◽  
Vol 898 ◽  
pp. 1051-1055 ◽  
Author(s):  
Hong Tao Liu ◽  
Ruo Chao Wang ◽  
Qing Liu ◽  
Ji Xue Zhou ◽  
Yan Fei Chen ◽  
...  
Keyword(s):  
Laser Welding ◽  
Nd:Yag Laser ◽  
Energy Dispersive Spectrometer ◽  
Base Material ◽  
Welding Process ◽  
Microstructure Characterization ◽  
Columnar Grains ◽  
Equiaxed Grains ◽  
Laser Welding Process

The Nd:YAG laser welding process of AZ31B alloys was performed by using the six-axis robot in this work. The microstructure characterization of AZ31B auto-welded joints was studied by using scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The laser welding process resulted in the formation of equiaxed grains in the center of the fusion zone (FZ) and columnar grains near the FZ boundary, meanwhile some eutectic β-Mg17Al12 particles were observed in the microstructure. No clear heat affected zone (HAZ) was observed in the welded AZ31B joint. Furthermore, some pores were observed in the base material (BM) and FZ.

scholarly journals Structural Transformations Versus Hard Particles Motion in the Brass Ingots

2017 ◽  
Vol 62 (4) ◽  
pp. 2461-2467 ◽  
Author(s):  
W. Wołczyński ◽  
A.A. Ivanova ◽  
P. Kwapisiński ◽  
E. Olejnik
Keyword(s):  
Continuous Casting ◽  
Thermal Gradient ◽  
Structural Transformations ◽  
Gradient Field ◽  
Hard Particles ◽  
Columnar Grains ◽  
Solid Liquid ◽  
Equiaxed Grains ◽  
Structural Zones

AbstractA mathematical method for the forecast of the type of structure in the steel static ingot has been recently developed. Currently, the method has been applied to structural zones prediction in the brass ingots obtained by the continuous casting. Both the temperature field and thermal gradient field have been calculated in order to predict mathematically the existence of some structural zones in the solidifying brass ingot. Particularly, the velocity of theliquidusisotherm movement and thermal gradient behavior versus solidification time have been considered. The analysis of the mentioned velocity allows the conclusion that the brass ingots can evince: chilled columnar grains-, (CC), fine columnar grains-, (FC), columnar grains-, (C), equiaxed grains zone, (E), and even the single crystal, (SC), situated axially. The role of the mentioned morphologies is analyzed to decide whether the hard particles existing in the brass ingots can be swallowed or rejected by the solid / liquid (s/l) interface of a given type of the growing grains. It is suggested that the columnar grains push the hard particles to the end of a brass ingot during its continuous casting.

Effect of Cooling Rate and Si Content on Solidification Characteristics of Silicon Steel during Near-Rapid Solidification

2010 ◽  
Vol 146-147 ◽  
pp. 1247-1251
Author(s):  
Lei Wang ◽  
Xian Yong He ◽  
Qin Peng ◽  
Rong Yang ◽  
Qi Jie Zhai
Keyword(s):  
Cooling Rate ◽  
Silicon Content ◽  
Physical Simulation ◽  
Silicon Steel ◽  
Strip Casting ◽  
Contraction Rate ◽  
Linear Contraction ◽  
Si Content ◽  
Equiaxed Grains ◽  
Twin Roll

The solidification characteristics of silicon steel in twin roll strip casting was studied by physical simulation. The experiments were designed to approximate the solidification conditions of twin roll strip casting. The strips with different cooling rate and different silicon content were prepared. The results show that the solidification structures of the strips with different cooling rate and different Si content are composed of columnar and equiaxed grains, and the solidification structures vary significantly. And with the decrease of cooling rate, the linear contraction rate decreases.

Lead-Free Cu-Si-Zn Brass with Tin Addition

2013 ◽  
Vol 802 ◽  
pp. 169-173 ◽  
Author(s):  
Sasiworada Puathawee ◽  
Siriporn Rojananan ◽  
Surasit Rojananan
Keyword(s):  
Silicon Content ◽  
Induction Furnace ◽  
Hardness Test ◽  
Graphite Crucible ◽  
Lead Free ◽  
Chemical Compositions ◽  
X Ray ◽  
Β Phase ◽  
Tin Content ◽  
Vickers Hardness Test

In this work, lead-free silicon brass (Cu-Si-Zn) with tin addition was studied to investigate on the comparative influence of the adding and non-adding tin on the microstructures and microhardness. In order to produce new alloy compositions, varied amount of silicon (0.5, 1.0, 2.0, 3.0 wt%) were incorporated. The ranges of chemical compositions were copper contents between 58.7 and 60.3 wt%, tin content 0.6 wt% and zinc remaining. The silicon brasses were prepared by melting pure elements with a graphite crucible using an induction furnace. The chemical composition of each alloy has been determined by X-ray fluorescence spectrometry (XRF). Microstructures of the as-cast silicon brass ingots have been observed by optical microscopy and scanning electron microscopy. The respective chemical analysis of the phases was determined by energy dispersive X-ray spectroscopy (EDS) and the hardness was measured by Vickers hardness test. The results revealed that the hardness of 60Cu-0.5Si-39.5Zn brass was 123.4 HV. The higher silicon content improved the higher hardness of samples. Moreover, the addition of tin together with silicon increased amount of beta (β) phase and more uniform dispersive gamma (γ) phase than those of the silicon addition alone. It could be concluded that the tin addition enhanced the hardness of lead-free Cu-Si-Zn brass and trended to be helpful for machining.

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