scholarly journals Abnormal Grain Growth Mechanism in the Twin-Roller Cast Al-Fe-Si Alloy in the Annealing Process

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Y. Z. Zhu ◽  
H. Peng ◽  
H. Huang ◽  
J. C. Li
Keyword(s):  
Grain Growth ◽  
High Strain ◽  
Orientation Angle ◽  
Casting Process ◽  
Annealing Process ◽  
Abnormal Grain Growth ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Novel Technology

The twin-roller casting process is a novel technology used to produce aluminium and other alloys. In this study, the Al-Fe-Si alloy was twin-roller cast into a billet with a thickness of 7.0 mm. This was followed by an annealing process at 480°C for 16 hours. Abnormal grains of more than 15 mm in the nominal diameter were found to have formed on the surface of the billet. Scanning electronic microscopy observation, energy diffraction spectrum, microarea X-ray diffraction, and electronic backscattered diffraction analysis were performed to study this abnormal grain growth. The results showed that abnormal grain nucleates in the region of (100) <001> texture formed in the twin-roller casting process. The growth of abnormal grain was governed by the coalescence of the abnormal grain with its surrounding normal grains, with an average orientation angle of 47° between both the types of grains. High-strain-concentrated regions on the surface layer of the billet were induced by the heterogeneously distributed Fe particles formed in the twin-roller casting process. The presence of these regions accelerates the abnormal grain growth in the following annealing process of the billet.

Abnormal Grain Growth on the Surface of Cold-Rolled AA1235 Aluminum Plate during the Annealing Process

2017 ◽  
Vol 898 ◽  
pp. 1123-1133
Author(s):  
Y.Z. Zhu ◽  
Xiao Hui Li ◽  
J.C. Li ◽  
Wei Long Fan ◽  
Cheng Wei Xia ◽  
...  
Keyword(s):  
Grain Growth ◽  
Orientation Angle ◽  
Abnormal Grain Growth ◽  
Bottom Surface ◽  
X Ray Diffraction ◽  
X Ray ◽  
Abnormal Growth ◽  
Cold Rolled ◽  
Twin Roll Cast ◽  
Twin Roll

AA1235 aluminum alloys were twin roll cast into a 7.0 mm-thick billet and further rolled into a plate with 70% reduction, followed by annealing at 500 C for 8 h. Abnormal grains were found to be formed on the plate bottom surface. SEM, EBSD, and micro X-ray diffraction were used to analyze the mechanism underlying the abnormal growth of these grains. Results showed that the {100} <001> texture was formed in the surrounding normal grains adjacent to the abnormal grain. The orientation angle between the abnormal grain and its adjacent normal grains was 45°. The {100} <001> texture formed during rolling and annealing accelerated abnormal grain growth. The partially dissolved Fe precipitates were heterogeneously distributed in the plate bottom heterogeneously, which also mainly explained abnormal grain growth.

Experimental Study for Ultra High Strength Strapping Flat Steel

2014 ◽  
Vol 490-491 ◽  
pp. 181-185
Author(s):  
Feng Li ◽  
Fang Zhou ◽  
Hong Gang Yang ◽  
Jia Shun Lv ◽  
Leng Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Retained Austenite ◽  
High Strength ◽  
Annealing Process ◽  
Continuous Annealing ◽  
Diffraction Spectrum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Flat Steel

Ultra high strength strapping flat steel is used in packaging for papermaking, tobacco, compressed cotton and wool. At present, there is only one company can produce it by Lead bath quenching line. In this paper, the feasibility to produce new ultra high strength strapping flat steel of which tensional strength is 1350 MPa and elongation is 12% by continuous annealing process was investigated. The experiment result of steelmaking, hot rolling, pickling, cold rolling and continues heat treatment showed, the steel could be got using new chemical composition. The microstructure and X-ray diffraction spectrum of the steel showed, the steel was strengthened and toughened by martensite and retained austenite. The effect of continues heat treatment on microstructure and mechanical properties was discussed.

Preparation and Characterisation of TiO2 Thick Films Fabricated by Electrophoretic Deposition

2007 ◽  
Vol 561-565 ◽  
pp. 2163-2166 ◽  
Author(s):  
H.Z. Abdullah ◽  
Charles C. Sorrell
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Grain Growth ◽  
Electrophoretic Deposition ◽  
Defect Formation ◽  
Titanium Foil ◽  
X Ray Diffraction ◽  
Voltage Range ◽  
X Ray ◽  
Scanning Electron

Rutile nano-powders were suspended in a solution of acetylacetone and iodine. The suspensions were electrophoretically deposited on titanium foil at a voltage range of 5-30 V over times of 5-120 s. The dried tapes then were sintered at 800°C for 2 h in flowing argon. Both the green and fired tapes were examined by field emission scanning electron microscopy, optical microscopy, X-ray diffraction, and Raman microspectroscopy. The thickness of the films depended on the voltage and the time of deposition. The sintered microstructures depended significantly on the thickness of the film, which was a function the proximity to the Ti/TiO2 interface. The interface is critical to the microstructure because it acts as the source of defect formation, which enhances sintering, grain growth, and grain facetting.

Microstructure Evolution of a Fine Grain Al-50wt%Si Alloy Fabricated by High Energy Milling

2011 ◽  
Vol 479 ◽  
pp. 54-61 ◽  
Author(s):  
Fei Wang ◽  
Ya Ping Wang
Keyword(s):  
Grain Growth ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Milling Time ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Laser Method ◽  
X Ray ◽  
Fine Grain

Microstructure evolution of high energy milled Al-50wt%Si alloy during heat treatment at different temperature was studied. Scanning electron microscope (SEM) and X-ray diffraction (XRD) results show that the size of the alloy powders decreased with increasing milling time. The observable coarsening of Si particles was not seen below 730°C in the high energy milled alloy, whereas, for the alloy prepared by mixed Al and Si powders, the grain growth occurred at 660°C. The activation energy for the grain growth of Si particles in the high energy milled alloy was determined as about 244 kJ/mol by the differential scanning calorimetry (DSC) data analysis. The size of Si particles in the hot pressed Al-50wt%Si alloy prepared by high energy milled powders was 5-30 m at 700°C, which was significantly reduced compared to that of the original Si powders. Thermal diffusivity of the hot pressed Al-50wt%Si alloy was 55 mm2/s at room temperature which was obtained by laser method.

Simulations of High-Strain Electrostrictive Chlorinated Terpolymers

2003 ◽  
Vol 785 ◽  
Author(s):  
George J. Kavarnos ◽  
Thomas Ramotowski
Keyword(s):  
Vinylidene Fluoride ◽  
High Strain ◽  
Polymer Chains ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lamellar Structures ◽  
Annealing Conditions ◽  
Poly Vinylidene Fluoride ◽  
Electromechanical Responses ◽  
Kinetics Of

ABSTRACTChlorinated poly(vinylidene fluoride/trifluoroethylene) terpolymers are remarkable examples of high strain electrostrictive materials. These polymers are synthesized by copolymerizing vinylidene fluoride and trifluoroethylene with small levels of a third chlorinated monomer. The electromechanical responses of these materials are believed to originate from the chlorine atom, which, by its presence in the polymer chains and by virtue of its large van der Waals radius, destroys the long-range crystalline polar macro-domains and transforms the polymer from a normal to a high-strain relaxor ferroelectric. To exploit the strain properties of the terpolymer, it is desirable to understand the structural implications resulting from the presence of the chlorinated monomer. To this end, computations have been performed on model superlattices of terpolymers using quantum-mechanical based force fields. The focus has been on determining the energetics and kinetics of crystallization of the various polymorphs that have been identified by x-ray diffraction and fourier transform infrared spectroscopy. The chlorinated monomer is shown to act as a defect that can be incorporated into the lamellar structures of annealed terpolymer without a high cost in energy. The degree of incorporation of the chlorinated monomer into the crystal lattice is controlled by annealing conditions and ultimately determines the ferroelectric behavior of the terpolymers.

Synthesis and Characterization of New Refractory Coatings Based on Talc, Cordierite, Zircon and Mullite Fillers for Lost Foam Casting Process

2014 ◽  
Vol 59 (1) ◽  
pp. 89-95 ◽  
Author(s):  
A. Prstić ◽  
Z. Aćimović-Pavlović ◽  
A. Terzić ◽  
L. Pavlović
Keyword(s):  
Microstructural Analysis ◽  
Casting Process ◽  
Lost Foam Casting ◽  
X Ray Diffraction ◽  
X Ray ◽  
Software Application ◽  
Design And Optimization ◽  
Refractory Coatings ◽  
Particle Size And Shape ◽  
Lost Foam

Abstract Refractory coatings based on different refractory fillers (talc, cordierite, zircon and mullite) for application in Lost Foam casting process were investigated. Design and optimization of the coatings composition with controlled, rheological properties included, and consequently synthesis were achieved by application of different coating components, namely different suspension agents and fillers and by alteration of the coating production procedure. Morphologic and microstructural analysis of fillers was carried out by means of scanning electronic microscope. X-ray diffraction analysis by means of X-ray diffractometer was applied in determination and monitoring the phase composition changes of the refractory fillers. An analysis of the particle size and shape was carried out by means of the PC software application package OZARIA 2.5. To assess the effects of application of individual refractory coatings, a detailed investigation of structural and mechanical properties of the moldings obtained was performed. Highlight was placed on revealing and analyzing surface and volume defects present on moldings. Radiographic molding tests were carried out by means of the X-ray device SAIFORT type-S200. Attained results are essential for the synthesis of refractory coatings based on high-temperature fillers and their applications in Lost Foam casting process for manufacturing of moldings with in-advance-set properties.

Effects of Surface Energy on the Microstructures of Thin Sb Films

1990 ◽  
Vol 202 ◽  
Author(s):  
L. H. Chou ◽  
M. C. Kuo
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Grain Growth ◽  
Grain Orientation ◽  
Thermal Evaporation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Transmission Electron ◽  
Diffraction Peaks

ABSTRACTThin Sb films have been prepared on glass substrates by rapid thermal evaporation. Films with thicknesses varied from 260 Å to 1300Å were used for the study. X-ray diffraction data showed that for films deposited at room substrate temperature, an almost random grain orientation was observed for films of 1300 Å thick and a tendency for preferred grain orientation was observed as films got thinner. For films of 260 Å thick, only two x-ray diffraction peaks--(003) and (006) were observed. After thermal annealing, secondary grains grew to show preferred orientation in all the films. This phenomenon was explained by surface-energy-driven secondary grain growth. This paper reports the effects of annealing time and film thickness on the secondary grain growth and the evolution of thin Sb film microstmctures. Transmission electron microscopy (TEM) and x-ray diffraction were used to characterize the films.

scholarly journals Kaolinite-Magnesite or Kaolinite–Talc-Based Ceramics. Part II: Microstructure and the Final Properties Related Sintered Tapes

Minerals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1080
Author(s):  
Aghiles Hammas ◽  
Gisèle Lecomte-Nana ◽  
Imane Daou ◽  
Nicolas Tessier-Doyen ◽  
Claire Peyratout ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Ceramic Industry ◽  
Raw Materials ◽  
Tape Casting ◽  
Casting Process ◽  
Aqueous System ◽  
Mechanical And Thermal Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Kaolinitic Clay

In recent decades, talc and kaolinite have been widely used as raw materials for the ceramic industry. In this study, the final characteristics of kaolinitic clay mixed with 6 mass% of magnesite obtained in our previous work were compared with those obtained with mixtures of kaolin (kaolin BIP) and talc (as the source of magnesium oxide). However, different amounts of talc in the kaolin powder were studied, namely 10, 30, and 50 mass% of added talc (with respect to kaolin + talc). The tape casting process was used during this work in order to manufacture the green tapes in an aqueous system with 0.2 mass% of dispersant. Subsequently, the green tapes were heated to 1000 and 1100 °C with a dwelling time of 12 min. The green and sintering tapes were characterized using the following techniques: DTA/TG, X-ray diffraction, porosity, and flexural strength analyses. The results obtained from our previous work indicate that the specimen with 6 mass% of MgCO3 sintered at 1200 °C for 3 h exhibited the best performances, with high flexural strength and weak porosity value—117 MPa and 27%—respectively. As results from this study, the optimal mechanical and thermal properties of sintering tapes were obtained for the specimen with 10 mass% of added talc sintered at 1100 °C. Indeed, this specimen exhibited 50 MPa and 43% of stress to rupture and apparent porosity, respectively.

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