scholarly journals Hot Ductility of TiNb IF Steel Slab after Hot Torsion Testing

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 752 ◽  
Author(s):  
Konrádyová ◽  
Longauerová ◽  
Jonšta ◽  
Jonšta ◽  
Longauer ◽  
...  
Keyword(s):  
Temperature Cycling ◽  
Hot Ductility ◽  
If Steel ◽  
Cast Slab ◽  
Torsion Testing ◽  
Steel Slab ◽  
Temperature Dependences ◽  
Hot Torsion ◽  
Average Size ◽  
20 Nm

The aim of the work was to evaluate the hot ductility loss in TiNb stabilized IF steel directly from the continuously-cast slab using hot torsion testing (plastometry) in the temperature range 600–1250 °C according to the basic programme, and also after temperature cycling. A good match of the temperature dependences of number of turns to failure (Nf) and intensity of deformation Se was confirmed. In both cases, the existence of three temperature areas with decrease in plasticity to a minimum was confirmed. The two-stage temperature cycling according to the CT1150 and CT900 programmes mostly resulted in a decrease in plasticity compared to the basic programme. The most significant effect of cycling was related to the CT900 programme below the maximum plasticity in the base programme at 850 °C. A less pronounced decrease was observed for CT1150 cycling below the maximum plasticity in the base program at 1050 °C. In the case of CT1150 cycling, more complex particles were observed at the fractures compared with the basic programme, namely carbonitrides of Ti and Nb in combination with oxisulfides respectively, then Ti nitrides with oxisulfides or oxides and, in addition, complex (Fe,Nb)P4, (Ti,Nb)3S4 type particles. Their mean size determined statistically using TEM was much finer, only 20 nm versus 42 nm in the basic programme. Similarly, CT900 cycling revealed finer particles with an average size of 37 nm compared to 105 nm in the basic programme. The observed particles were Al oxides, Ti(N,C) and (Ti,Nb)2S, in contrast to the particles probably of TiFe and FeMnS in the basic programme. The decrease in plasticity corresponded to the finer particles, newly created in the temperature cycling.

Interrelationship between Hot Ductility and Particle Size in TiNb IF Steel

2017 ◽  
Vol 891 ◽  
pp. 124-130 ◽  
Author(s):  
Jana Konrádyová ◽  
Margita Longauerová ◽  
Vladimír Girman ◽  
Svätoboj Longauer ◽  
Aleš Bořuta ◽  
...  
Keyword(s):  
Particle Size ◽  
Hot Ductility ◽  
If Steel ◽  
Critical Temperatures ◽  
Transmission Electron ◽  
Large Particles ◽  
Minimum Number ◽  
Hot Torsion ◽  
Size Of Particles ◽  
The Relationship

The aim of this work was to observe the relationship between hot ductility and morphology, distribution and size of particles in TiNb IF steel after hot torsion testing at the critical temperatures of deformation with low as well as maximum values of plasticity. Transmission electron microscopy showed that the particles at all temperatures of deformation with minimum number of turns to failure e.g. 1132°C (33.72 rev.), 946°C (6.24 rev.), 637°C (5.54 rev.) as well as with maximum value of plasticity at 844°C (1726 rev.) were of globular, cuboid or elliptical shape. EDX analysis revealed that there were different types of particles such as carbides, sulfides, and carbonitrides of Ti and Nb, Al and Si oxides, Mn sulfides, and phosphides. Quantitative evaluation of particle size in the carbon extracted replicas showed 20% of total number of particles with size 2r = 30-39 nm and an average linear dimension = 42 nm at the deformation temperature of 1132°C. There were 28% of the particles with size 2r = 20-29nm and = 41nm at the temperature of 946°C while at the temperature of 637°C there were 29% of particles with size 2r = 20-29 and 26% with size 2r=10-19 nm and = 41 nm. In the case of maximum plasticity (1726 rev.) at 844°C, the presence of large particles was confirmed with = 105 nm size and 9% distribution in three size categories of 20-29, 30-39, 90-99 nm.

Precipitation Upon Hot Strip Mill Conditions of a Ti-IF Steel

2001 ◽  
Vol 7 (S2) ◽  
pp. 508-509
Author(s):  
W. Regone ◽  
A. M. 𝚓orge Júnior ◽  
O. Balancin
Keyword(s):  
Hot Strip Mill ◽  
Interstitial Free ◽  
If Steel ◽  
Precipitation Sequence ◽  
Hexagonal Crystal Structure ◽  
Hexagonal Crystal ◽  
Hot Strip ◽  
Hot Torsion ◽  
And Diffusion ◽  
Interstitial Elements

Upon hot strip mill of titanium Interstitial Free (IF) steels, during cooling from austenite to ferrite region, the level of interstitial elements not removed by steelmaking process is dropped down by Ti that combines with N, C and S. Some authors [1-3] have reported that the traditional precipitation sequence TiN, TiS, Ti4C2S2 and TiC occurs with freestanding particles formed by nucleation and growth processes. Other authors [4] have indicated that the transformation from TiS to Ti4C2S2 may be considered as a hybrid of shear and diffusion, i.e., faulted Ti8S9 (9R) + 10[Ti] + 9[C] → 41/2Ti4C2S2 (or H for its hexagonal crystal structure). At low temperature (≤930°C), the stabilization process continues through epitaxial growth of carbides on H phase. to study the evolution of precipitation upon hot strip mill conditions, samples of a Ti - IF steel were subjected to double straining tests [5] by means of a computerized hot torsion machine, at 1000 °C and 920 °C, with strain rate of 1 s-1 and interpass times ranging from 0.5 to 100 s.

Formation of Core-Shell Nanoparticles by Laser Ablation of Copper and Brass in Liquids

2005 ◽  
Vol 106 ◽  
pp. 23-26 ◽  
Author(s):  
P.V. Kazakevich ◽  
A.V. Simakin ◽  
V.V. Voronov ◽  
G.A. Shafeev ◽  
D. Starikov ◽  
...  
Keyword(s):  
Core Shell ◽  
Copper Vapour Laser ◽  
Shell Nanoparticles ◽  
Liquid Environment ◽  
Pulsed Nd:Yag Laser ◽  
Plasmon Peak ◽  
Average Size ◽  
Core Shell Nanoparticles ◽  
20 Nm ◽  
Surrounding Liquid

Experimental results are presented on the ablation of copper and brass targets in a liquid environment: ethanol, acetone, or water by irradiation with either a pulsed copper vapour laser (0.51 μm) or a pulsed Nd:YAG laser (1.06 μm). The ablated material was ejected into the surrounding liquid as nanoparticles of average size 20 nm. The nanoparticle composition depends on the nature of the liquid. Ablation of 60%Cu, 40%Zn brass in ethanol results in formation of core-shell nanoparticles. Brass nanoparticles were characterized by a well-defined plasmon peak at 510-520 nm.

scholarly journals Effects of Current on Arc Fabrication of Cu Nanoparticles

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
M. Z. Kassaee ◽  
F. Buazar ◽  
E. Motamedi
Keyword(s):  
Thermal Stability ◽  
Distilled Water ◽  
Face Centered Cubic ◽  
Cu Nanoparticles ◽  
Dta Analysis ◽  
Face Centered ◽  
Average Size ◽  
20 Nm ◽  
Thermal Stability Of ◽  
Sem Analyses

Arc-fabricated copper nanoparticles (Cu Nps) size, morphology and the crystalline structure, as well as the yields of Nps appear sensitive to the applied currents (50–160 A) in distilled water. The results indicate that the sizes of Cu Nps are directly proportional to the currents employed. At 50 A, TEM, XRD, and SEM analyses show fabrication of relatively purest, the most dispersed, face-centered cubic (fcc) brown Cu Nps with rather smallest average size of 20 nm. At the same current, the TGA-DTA analysis reveals neither weight loss nor gain, indicating thermal stability of the fabricated Cu Nps.

Scandium (Sc) Behavior in High Temperature Ti Alloys

2012 ◽  
Vol 520 ◽  
pp. 57-62
Author(s):  
De Hai Ping ◽  
S.Q. Wu ◽  
Y. Yamabe-Mitarai
Keyword(s):  
Elevated Temperatures ◽  
High Strength ◽  
High Density ◽  
Free Zone ◽  
Minor Addition ◽  
Ti Alloys ◽  
Elevated Temperature Tensile ◽  
Sc Addition ◽  
Average Size ◽  
20 Nm

The microstructural evolution and elevated temperature tensile properties of Ti-6.6Al-5.2Sn-1.8Zr-(0~3.8)Sc (wt%) alloys have been investigated. The Sc-added alloys showed improved yield strength at 650°C and 750°C and with the elongation above 10%. Minor addition of Sc was found to significantly reduce the as-cast grain size. Higher amount of Sc additions resulted in the formation of high density of Sc-oxide, which causes the high strength at elevated temperatures and the reduction of ductility. High density of α2-Ti3Al fine precipitates with an average size of about 20 nm were observed inside equiaxed primary α (αp) grains in the Sc-free or minor Sc added alloys. However, precipitation free zone (PFZ) also formed in those alloys, where grain boundaries are free from any precipitates. Higher Sc addition was found to hinder the formation of PFZ and α2–precipitates.

Bi-combustion synthesis technique for the reduction of crystallite size of nanophosphors - a modified version

2021 ◽  
pp. 1469-1475
Author(s):  
D. S. Kshatri, Shubhra Mishra, Vikas Dubey
Keyword(s):  
Crystallite Size ◽  
Combustion Synthesis ◽  
High Efficiency ◽  
Milling Process ◽  
Synthesis Technique ◽  
Crystallite Sizes ◽  
Average Size ◽  
20 Nm ◽  
Physical And Chemical ◽  
Combustion Synthesis Technique

Nanophase materials, in recent times, have attracted many a researcher all over the world, on account of their exceptionally high efficiency in terms of morphological and optical behavior. In the nano-range order, various physical and chemical methods are employed to produce materials commercially, but the reported methods owing to their own physical conditions, limit the crystallite sizes to a certain nano-order. To prevail over this size-related limitation, a new modified bi-combustion synthesis technique (B-CST) has been introduced, which aids inthe formation of nanomaterials, with an average size of 10-20 nm, without using any ball milling process. In order to scrutinize the crystallite sizes of SrAl2O4: Eu2+, Dy3+ phosphors synthesized by CST and B-CST, the X-ray diffraction (XRD) technique is used to determine the crystalline phase only while high-resolution transmission electron microscopy (HRTEM) is used, which is the most sought-after method world-wide and is vigorously used to determine the crystallite size.

Synthesis of Silica Aerogel Using Silica Sol by Ambient Drying Method

2017 ◽  
Vol 726 ◽  
pp. 199-203 ◽  
Author(s):  
Da Sun ◽  
Xue Ye Sui ◽  
Chang Ling Zhou ◽  
Nai Hong Han ◽  
Fu Tian Liu
Keyword(s):  
Pore Volume ◽  
Silica Aerogel ◽  
Normal Pressure ◽  
Silica Sol ◽  
Raw Material ◽  
Drying Method ◽  
Gel Time ◽  
Drying Temperature ◽  
Average Size ◽  
20 Nm

In this experiment, silica sol was used as raw material, the mixture of ammonium chloride and ammonia was used as coagulant. After replacing the solvent with n-hexane, silica aerogel was obtained under the condition of normal pressure. The influence of sol pH and coagulating temperature on the gel time was studied. According to the SEM photographs, the influence of drying temperature from 30 °C to 60 °C on the microstructure of silica aerogel was analyzed. This study showed that when sol pH was 6.5, coagulating temperature was 80 °C and the concentration of ammonia was 0.4 mol/L, the gel time was the shortest. The average size of silica aerogel particles was 10-20 nm, the average size of apertures was 20-50 nm. When the drying temperature was 40 °C, the specific surface area was 402.41 m2/g, the pore volume was 2.33 cm3/g, the density was 0.18 g/cm3.

A New Method for Preparing Ge Nano-Crystallites Embedded in SiNY Matrices

1994 ◽  
Vol 358 ◽  
Author(s):  
Kunji Chen ◽  
Xuexuan Qu ◽  
Xinfan Huang ◽  
Zhifeng Li ◽  
Duan Feng
Keyword(s):  
Laser Annealing ◽  
Hydrogen Plasma ◽  
New Method ◽  
Transmission Electron ◽  
Scattering Spectra ◽  
Ion Laser ◽  
New Type ◽  
Raman Scattering Spectra ◽  
Average Size ◽  
20 Nm

ABSTRACTWe report a new method for synthesizing Ge nano-crystallites embedded in SiNy film matrices. On the basis of the effect of the reactant precursors and preferential chemical bonding of Si-N and Ge-Ge, thin films with Ge clusters embedded in SiNy matrices have been prepared in the PECVD system with reactant gases of SiH4, GeH4 and NH3 mixed in the hydrogen plasma. The as-deposited films were then crystallized by Ar ion laser annealing or thermal annealing technique to form nanometer-sized Ge crystallites.The composition and microstructures of these new type of sample were characterized by infrared absorption spectra, transmission electron microscopy, X-ray diffraction and Raman scattering spectra. The results indicated that the average size of Ge crystallites was estimated to be 2-20 nm depending on the deposition and annealing parameters and can be controlled by a designed manner.

scholarly journals Formula-Driven, Size-Tunable Synthesis of PMMA Nanoparticles by Varying Surfactant Concentration

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1834
Author(s):  
Brian L. Kamras ◽  
Nooshin Mirzanasiri ◽  
Daniel K. Korir ◽  
Sujata Mandal ◽  
Shreya L. Hariharakumar ◽  
...  
Keyword(s):  
Surfactant Concentration ◽  
Size Range ◽  
Sodium Dodecyl ◽  
Synthetic Method ◽  
Decay Function ◽  
Amine Functionalized ◽  
Independent Variable ◽  
Average Size ◽  
20 Nm ◽  
Size Data

In this communication, we present a streamlined, reproducible synthetic method for the production of size-tunable poly(methyl methacrylate) (PMMA) nanoparticles (PMMANPs) and amine-functionalized block-copolymer PMMANPs (H2N-PMMANPs) by varying subcritical concentrations (i.e., below the concentration required to form micelles at 1 atm and 20 °C) of sodium dodecyl sulfate (SDS). We plotted the Z-average size data against SDS concentration, which revealed a second-order exponential decay function, expressed as A 1 e − x t 1 + A 2 e − x t 2 + y 0 . The surfactant concentration (wt./wt.%) has been selected as independent variable x. This function is valid at least for the size range of 20 nm to 97 nm (PMMANPs) and 20 nm to 133 nm (H2N-PMMANPs).

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