scholarly journals Influence of Intermediate Annealing Treatment on the Kinetics of Bainitic Transformation in X37CrMoV5-1 Steel

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4411
Author(s):  
Grzegorz Łukaszewicz ◽  
Krzysztof Wasiak ◽  
Emilia K. Skołek ◽  
Ryszard Diduszko ◽  
Wiesław A. Świątnicki
Keyword(s):  
Computer Simulations ◽  
Concentration Distribution ◽  
Annealing Treatment ◽  
Xrd Analysis ◽  
Bainitic Transformation ◽  
Intermediate Annealing ◽  
Isothermal Heating ◽  
New Process ◽  
Kinetics Of ◽  
Economical Process

Intermediate annealing treatment (IAT) is a new process that accelerates the bainitic transformation in steels. This stimulation is crucial, especially in the prolonged production of nanobainitic steels. Among other recognised methods, it seems to be an effective and economical process. However, there are very few research works in this area. The objective of this study was to collate microstructural changes caused by IAT with differences in the kinetics of the subsequent bainitic transformation in the X37CrMoV5-1 tool steel. Differential dilatometry, LM and SEM microscopic observations, EDS and XRD analysis, and computer simulations were used to investigate the effect of IAT on the kinetics of bainitic transformation. The study has revealed that introducing an additional isothermal heating stage immediately after austenitising significantly affects the kinetics of bainitic transformation—it can accelerate or suppress it. The type and strength of the effect depends on the concentration, distribution, and morphology of the precipitations that occurred during IAT.

The absorption spectra of irradiated diamonds after heat treatment

1956 ◽  
Vol 237 (1208) ◽  
pp. 75-89 ◽  
Keyword(s):  
Absorption Spectra ◽  
Absorption Lines ◽  
Type I ◽  
Type Ii ◽  
Large Reduction ◽  
Isothermal Heating ◽  
Interstitial Carbon ◽  
Crystal Imperfections ◽  
Continuous Absorption ◽  
Kinetics Of

The absorption spectra of eight type I and three type II a diamonds irradiated with neutrons, electrons or y-rays have been recorded at 80 and 290°K after various heat treatments in the temperature range 0 to 900°C. It is found that heating in the range 350 to 450°C causes a general reduction in the irradiation-induced absorption owing to the recombination of those interstitials and vacancies which are near neighbours. Heating type II a diamonds at 600°C causes a large reduction in the irradiation-induced lines and new lines appear. These are probably due to pairs of identical defects, and the kinetics of their formation during isothermal heating at 600°C are presented. At higher temperatures all absorption lines in type II a diamonds disappear and only continuous absorption remains. This is probably due to amorphous or graphitic regions produced by agglomeration of defects. Type I diamonds show the same kind of absorption, but in addition show an increase in strength of the natural lines and also some new absorption lines which are not removed by heating at 900°C. It is suggested that these additional processes are due to the anchoring of vacant atomic sites and interstitial carbon atoms at crystal imperfections present only in type I diamonds.

scholarly journals Corrosion Behaviour of Passive Layer Growth by Controlling Additives of Nano-Metals-Phosphate to Pure Aluminum

2020 ◽  
Vol 13 (4) ◽  
pp. 1-9
Author(s):  
Hussein A. Hussein ◽  
Mohammed J. Kahdim ◽  
Alaa Abdulhasan Atiyah
Keyword(s):  
Aluminum Oxide ◽  
Corrosion Behaviour ◽  
Pure Aluminum ◽  
Xrd Analysis ◽  
Passive Layer ◽  
Layer Growth ◽  
Metal Phosphate ◽  
Cyclic Polarization ◽  
Cast Sample ◽  
Kinetics Of

This study investigates how microstructure and chemistry effects by Nano-Metal-Phosphate and the kinetics of growth passive layer and passivity breakdown. Additionally, the passive layer germination behavior on aluminum alloy 1050 with anticorrosive properties. The passive layer is an alloying method which allows an aluminum oxide to germinate. Morphologically and structurally, the aluminum oxide films were characterized using microscopy analyzes and XRD analysis. Results indicated that the reinforcements are well distributed and the grin size is downy. Corrosion behavior tested by Cyclic polarization exam and done at room temperature in (3.5 per cent NaCl) solution. The reinforcement increased the hardness for processed aluminum from Hv81.1 to HV=120.492 as castings. The parameter Nano-Metal-Phosphate has attenuated the current density of corrosion (7.15μA / cm2) compared to the as-cast sample results.

In situ synchrotron XRD analysis of the kinetics of spodumene phase transitions

2018 ◽  
Vol 20 (16) ◽  
pp. 10753-10761 ◽  
Author(s):  
Radhika L. Moore ◽  
Jason P. Mann ◽  
Alejandro Montoya ◽  
Brian S. Haynes
Keyword(s):  
Phase Transitions ◽  
Kinetic Model ◽  
Xrd Analysis ◽  
Kinetics Of ◽  
Synchrotron Xrd

A kinetic model for the decomposition of α-spodumene and γ-spodumene is derived using in situ XRD to monitor the transitions.

scholarly journals Combined Effects of Deformation and Undercooling on Isothermal Bainitic Transformation in an Fe-C-Mn-Si Alloy

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 138 ◽  
Author(s):  
Hang Zou ◽  
Haijiang Hu ◽  
Guang Xu ◽  
Ziliu Xiong ◽  
Fangqin Dai
Keyword(s):  
Transformation Temperature ◽  
Bainitic Transformation ◽  
Combined Effects ◽  
Medium Carbon ◽  
Thermomechanical Simulation ◽  
Higher Temperature ◽  
The Difference ◽  
The Individual ◽  
Isothermal Bainitic Transformation ◽  
Kinetics Of

Both ausforming and transformation temperature affect the successive bainitic transformation and microstructure. The individual influence of each case is clear, whereas the combined effects are still unknown. Thermomechanical simulation and metallography were used to investigate the combined effects of ausforming and transformation temperature on bainitic transformation and microstructure. The kinetics of isothermal bainitic transformation in non-deformed and deformed materials was analyzed. A lower transformation temperature can lead to more bainite formation without deformation. However, ausforming with small strains can partially compensate for the decrease of bainite amount caused by the decreased undercooling. The larger the applied strain is, the smaller the difference between the final amounts of bainite with different undercooling. Ausforming at a relatively higher temperature is more favorable to the acceleration of subsequent isothermal bainitic transformation. The results in the present work provide reference for optimizing the fabrication technology of medium-carbon nanobainite steels.

Kinetics and Mechanism of the Microwave Synthesis of Barium Titanate

1996 ◽  
Vol 430 ◽  
Author(s):  
Hanlin Zhang ◽  
Shixi Ouyang ◽  
Hanxing Liu ◽  
Yongwei Li
Keyword(s):  
Activation Energy ◽  
Solid State ◽  
Microwave Field ◽  
Formation Rate ◽  
Xrd Analysis ◽  
Conventional Heating ◽  
Heating Process ◽  
Formation Kinetics ◽  
Kinetics Of ◽  
Synthesis Of Barium Titanate

AbstractThe formation kinetics of BaTiO3from the solid-state BaCO3and TiO2powder in a microwave field was investigated. The quantitative XRD analysis and the model considered the volume change between reactant and product were used in this experiment. Results show that the formation rate of BaTiO3in a microwave field is much faster than upon conventional heating. The activation energy of the solid state reaction for BaTiO3was measured as 58 kJ/mol. This indicates the enhancement of diffusion by the microwave heating process.

scholarly journals Effect of the Noble Metals Addition on the Oxidation Behavior of Ni3Al

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
J. J. Ramos-Hernandez ◽  
J. Porcayo-Calderon ◽  
J. G. Gonzalez-Rodriguez ◽  
Jan Mayén ◽  
G. Lara-Rodriguez ◽  
...  
Keyword(s):  
Noble Metals ◽  
Oxidation Behavior ◽  
Surface Composition ◽  
Xrd Analysis ◽  
Intermetallic Alloy ◽  
Oxide Growth ◽  
X Ray ◽  
Crystallographic Planes ◽  
Kinetics Of ◽  
Duplex Oxide

This paper discusses the effect of the addition of noble metals on the microstructure, mechanism, and oxidation kinetics of the Ni3Al intermetallic alloy. Ni3Al was doped with 1% (atomic percent) of Au, Ag, Pd, and Pt. Oxidation behavior of the alloys was evaluated at 900, 1000, and 1100°C in O2 for 24 hours. XRD analysis showed that the addition of noble metals favored the oxide growth on preferential crystallographic planes. In addition, the preferential substitution of the noble metals in the Ni3Al structure modifies the surface composition by increasing the Al/Ni ratio. It was observed that most of the alloys showed a subparabolic behavior, and only the intermetallic base and the alloy doped with Ag show a parabolic behavior at 900°C. The developed oxides were analyzed both superficially and in cross section by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA). It was evident that only the intermetallic base showed the formation of a duplex oxide scale (Al2O3/NiO). The alloys doped with noble metals showed the oxide growth practically of pure Al2O3. This was due to a decrease in the diffusion of the Ni cations because of the presence of the noble metals in the crystalline structure.

The Correlation Theory of 2D Normal Grain Growth

2004 ◽  
Vol 467-470 ◽  
pp. 1081-1086 ◽  
Author(s):  
M.W. Nordbakke ◽  
N. Ryum ◽  
Ola Hunderi
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Growth ◽  
Grain Size Distribution ◽  
Computer Simulations ◽  
Mean Field Theory ◽  
Mean Field ◽  
Grain Structures ◽  
Spatial Grain ◽  
Kinetics Of

Computer simulations of 2D normal grain growth have shown that size correlations between adjacent grains exist in 2D grain structures. These correlations prevail during the coarsening process and influence on the kinetics of the process and on the grain size distribution. Hillert’s analysis starts with the assumption that all grains in the structure have the same environment. Since computer simulations contradict this assumption, the mean-field theory for normal grain growth needs to be modified. A first attempt was made by Hunderi and Ryum, who modified Hillert’s growth law to include the effect of spatial grain size correlations. In the 1D case the distributions derived by means of the modified growth law agreed well with simulation data. However, the distribution derived for 2D grain growth retained unwanted properties of the Hillert distribution. We review some recent progress in developing a mean-field statistical theory. A paradox related to curvilinear polygons is shown to support the expectation that the grain size distribution has a finite cutoff.

Effect of Aluminum Addition on the Static Recrystallization Behavior of Magnesium

2012 ◽  
Vol 724 ◽  
pp. 163-168 ◽  
Author(s):  
Keun Joon Kim ◽  
Tae Kwon Ha
Keyword(s):  
Static Recrystallization ◽  
Solution Treatment ◽  
Annealing Treatment ◽  
Hardness Measurement ◽  
Recrystallization Behavior ◽  
Microstructure Observation ◽  
Heat Treated ◽  
Increasing Temperature ◽  
Kinetics Of ◽  
Rolled Plates

Recrystallization kinetics of Mg alloy has been investigated in this study. Mg alloys such as Mg-3Al and Mg-6Al in weight percents were cast into rectangular shaped ingots of 20mm thickness. Solution treatment at 400°C for 24 hrs has been carried out on these ingots and pure Mg for comparison. Heat treated ingots including pure Mg were rolled at room temperature by thickness reductions of 10, 20, and 30 percents. Annealing treatment for recrystallization has been conducted on these cold-rolled plates at temperatures of 200, 300, and 400°C for various times from 1 min to 24 hrs. The microstructure observation and hardness measurement conducted on the recrystallized specimens revealed that static recrystallization at 200°C was very slow and expedited with increasing temperature, regardless of Al contents. While recrystallization behavior of Mg at 300°C appeared to be retarded by increase in Al contents, that of Mg was not affected at 400°C.

Study of the Kinetics of Hydration Process of Anhydrite Using External Exciters

2013 ◽  
Vol 838-841 ◽  
pp. 2342-2345 ◽  
Author(s):  
Dominik Gazdič ◽  
Marcela Fridrichová ◽  
Karel Kalivoda ◽  
Jana Stachová
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Hydrated Lime ◽  
Xrd Analysis ◽  
Sodium Sulphate ◽  
Hydration Process ◽  
Gravimetric Analysis ◽  
Technological Properties ◽  
Thermo Gravimetric ◽  
Kinetics Of

Due to the very gradual hydration of anhydrites and their very low strengths, modification of the properties of anhydrite by a suitable external exciter was resolved within the work. The experimental work was conducted on natural anhydride, and as possible exciters for hydration, the following products were selected and tested: water-free sodium sulphate; Portland cement CEM I 42,5 R; hydrated lime CL 90 Carmeuse. The dose of the exciter was consistent, i.e. 4.5 wt%. The affect on the increased speed of the hydrating process and the quality of the technological properties was monitored. The catalytic effect was evaluated by monitoring the course of the hydration process (using XRD analysis and thermo-gravimetric analysis) and also on the basis of the achieved technological properties.

Sign in / Sign up

Export Citation Format

Share Document