Kinetics of Growth of Gas-Saturated (Embrittled) Layers on Titanium during Vacuum Annealing

2021 ◽  
Vol 316 ◽  
pp. 821-826
Author(s):  
Alexey B. Bulkov ◽  
Vladimir V. Peshkov ◽  
Vladimir F. Selivanov
Keyword(s):  
Experimental Data ◽  
Titanium Alloy ◽  
Growth Kinetics ◽  
Annealing Temperature ◽  
Vacuum Annealing ◽  
Surface Cracks ◽  
Brittle Crack ◽  
Parabolic Relationship ◽  
Kinetics Of ◽  
Annealing Mode

The influence of the parameters of the vacuum annealing mode on the thickness of the embrittled layers, formed on the surface of titanium as a result of its interaction with the residual gases of the vacuumed space, is studied. The thickness and structure of the layers were determined on samples made of VT6 alloy obtained from sheet metal with a thickness of 3 mm. Annealing of samples in the temperature range of 500-750 °C was performed with air dilution from 10 to 3∙10-2 PA. The dimensions of the embrittled layers were determined by measuring the zone of brittle crack propagation in the fracture of the samples, and measuring the distance between the surface cracks in the embrittled layers, formed during bending deformation. To quantify the effect of vacuum annealing modes of sheet titanium alloy VT6 on the depth of the embrittled part of the formed oxide layer, it is proposed to use a parabolic relationship, characterized by the degree of growth and the constant of the embrittled layer. By processing experimental data, the effect of annealing time, temperature, and air dilution on the growth kinetics of the embrittled layers was established. Based on the obtained kinetic regularities of the growth of the embrittled layers, nomograms are constructed, to determine the size of the embrittled layer formed at the heating stage at different speeds up to the specified annealing temperature.

Study of Donor Centres in n-InSb due to the Temperature Annealing

2005 ◽  
Vol 480-481 ◽  
pp. 197-200
Author(s):  
Y. Sayad ◽  
A. Nouiri
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Theoretical Study ◽  
Donor Concentration ◽  
Model Based ◽  
Proposed Model ◽  
Kinetics Of ◽  
Best Fit

An increasing of donor centres has been detected in n-InSb when it was submitted to anneal/quench with various annealing temperature (450 °C - 850 °C) and various annealing time (5 - 100 hours). A theoretical study of the kinetics of the conduction conversion of n-InSb at temperature annealing above 250 °C has been made. The present analysis indicates that the donor concentration increases with increasing of annealing time. In order to study this variation and to give a model for donor centres generated, a proposed model based on the simple kinetic is used to fit the variation of donor concentration as a function of annealing time. However, from the best fit of experimental data using the proposed model, the activation energy is determined.

Growth Kinetics of Interfacial Intermetallic Compound in Al(AA4343)/Steel(SUS316) Clad Strip

2020 ◽  
Vol 993 ◽  
pp. 447-456
Author(s):  
Xiao Jun Zhang ◽  
Kun Yuan Gao ◽  
Xiu Hua Hu ◽  
Yu Sheng Ding ◽  
Guo Zhan Wang ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Annealing Temperature ◽  
Optical Microscope ◽  
Alloy Layer ◽  
Kinetics Analysis ◽  
Growth Constant ◽  
Transmission Electron ◽  
Dispersive System ◽  
The Relationship ◽  
Kinetics Of

The composition and microstructure of intermetallic compounds (IMC) at the interface of aluminum(AA4343)-stainless steel(SUS316) were studied upon annealing at 550°C for 1h to 20h and at 610°C for 15min to 10h by means of optical microscope(OM) , scanning electron microscope (SEM) with energy dispersive system(EDS) and transmission Electron Microscopy (TEM). The results showed that the IMC was of 4.3μm to 36.1μm thick during heat treatment at 550°C for 1h to 20h, and the IMC contained Al-Fe-Si-Cr-Ni-Mo and Al-Fe-Si -Ni. During annealing at 610°C for 15min to 5h, the thickness of IMC was 31.2 μm to 208 μm, and the IMC were mainly of η-Fe2Al5 and τ10- Al4Fe1.7Si at 550°C for 10h. As the annealing time extended to 10h, natural delamination occurred at the interface between the aluminum alloy layer and IMC layer. The growth kinetics analysis showed that the relationship between the thickness of IMC “X” and time “t” followed the relational equation X=(kt)n. For AA4343(solid) - SUS316(solid), n was 1/2, and the growth constant k = 1.9×10-13m2/s at annealing temperature of 550 °C. When the temperature was 610°C, AA4343 - SUS316 was a liquid-solid contact reaction, n was 1, the growth constant k=1.45×10-8m/s.

scholarly journals STUDY THE GROWTH KINETICS OF PEDIOCOCCUS ACIDILACTICI WITH ESTIMATION OF KINETIC PARAMETERS AND APPLIED IN LARGE SCALE PEDIOCIN PRODUCTION

2016 ◽  
Vol 9 (5) ◽  
pp. 130
Author(s):  
Barnali Mandal
Keyword(s):  
Experimental Data ◽  
Lactic Acid ◽  
Kinetic Parameters ◽  
Growth Kinetics ◽  
Large Scale ◽  
Scale Up ◽  
Small Scale ◽  
Pediococcus Acidilactici ◽  
Monod Model ◽  
Kinetics Of

ABSTRACTObjectives: The aim of the study was to determine the growth kinetics of Pediococcus acidilactici using a mathematical model for large scale pediocinproduction.Methods: Growth kinetics of P. acidilactici has been studied for pediocin production in small scale batch fermenter (Erlenmeyer flask) using meatprocessing waste medium. The experiments have been conducted with varying the concentrations of glucose, protein, and lactic acid. A mathematicalmodel has been developed to describe growth rate, products (pediocin and lactic acid) formation rate, and substrates (glucose and protein) utilizationrate. Monod model for dual substrates (glucose and protein) has been used with considering lactic acid inhibition. Luedeking-Piret model has beenintroduced to describe the production of pediocin and lactic acid.Results: The values of kinetic parameters have been determined using experimental data and model equations. The model prediction has beencompared satisfactorily with the experimental data for the validation of the model.Conclusions: The developed model was satisfactorily validated to scale up the production of pediocin.Keywords: Pediococcus acidilactici, Pediocin, Meat processing waste, Monod model, Luedeking-Piret model, Kinetic parameters.

An Approach for Analyzing the Growth Kinetics of Fe2B Phase on AISI 1018 Steel

2010 ◽  
Vol 297-301 ◽  
pp. 269-274 ◽  
Author(s):  
Mourad Keddam
Keyword(s):  
Experimental Data ◽  
Carbon Steel ◽  
Growth Kinetics ◽  
Boron Content ◽  
Kinetic Constant ◽  
Mass Gain ◽  
Iron Boride ◽  
Simulation Results ◽  
Kinetics Of ◽  
Good Agreement

A simulation of the growth kinetics of iron boride forming on AISI 1018 carbon steel was done on the basis of a kinetic model. This model including the effect of the incubation time during the formation of iron boride, was applied in order to evaluate the kinetic constant at the ( ) interface, the layer thickness and the mass gain depending on the paste-boriding parameters such as time, temperature and boron potential reflected by the corresponding value of the surface boron content. The simulation results were found to be in a good agreement with the experimental data derived from the literature.

Changes in the structural and textural state of titanium alloy VT41 after hot upsetting and annealing

2021 ◽  
pp. 40-50
Author(s):  
P. N. Medvedev ◽  
S. A. Naprienko ◽  
O. S. Kashapov ◽  
E. V. Filonova
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Gas Turbine ◽  
Structural Changes ◽  
Annealing Temperature ◽  
Alloy Structure ◽  
Turbine Engine ◽  
Α Phase ◽  
Deformed State ◽  
Kinetics Of

A study of the structure of titanium alloy VT41 (Ti–Al–Si–Zr–Sn– β-stabilizers) was carried out on a sample subjected to hot upsetting in the (α+β)-region – conditions simulating the stamping of a disk of a gas turbine engine (GTE). The features of the formation of the textural state of primary and secondary globular grains, as well as the kinetics of their dissolution with an increase in the annealing temperature, have been determined. As a result of heat treatment at 995°C, the homogeneity of the alloy structure significantly increases comparing to the deformed state, which is associated with the recrystallization of lamellar and small-globular grains and the retention of primary globular grains of the α-phase. The sequence of structural changes has been established during the annealing within the temperature range from 950 to 1040°C.

Grain Growth Kinetics of Accumulative Roll Bonded AZ61 Alloy

2012 ◽  
Vol 585 ◽  
pp. 387-391 ◽  
Author(s):  
H. Shivananda Nayaka ◽  
Gajanan P. Chaudhari ◽  
B.S. Sunder Daniel
Keyword(s):  
Grain Growth ◽  
Growth Kinetics ◽  
Annealing Temperature ◽  
Isothermal Annealing ◽  
Arrhenius Equation ◽  
Growth Exponent ◽  
Az61 Magnesium Alloy ◽  
Ultrafine Grained ◽  
Grain Growth Kinetics ◽  
Kinetics Of

A detailed study was performed on the grain growth kinetics of ultrafine-grained AZ61 magnesium alloy produced by accumulative roll bonding by carrying out isothermal annealing treatments on the roll bonded samples. Annealing treatments were carried out in the temperature range 423 to 573K for 2 to 120 minutes. As the annealing time and temperature increased, the grain size increased. The effect of annealing temperature and time, on the grain growth can be well explained by the kinetic equation and Arrhenius equation. Based on the experimental results of grain growth during annealing treatments, the grain growth exponent and the activation energy for grain growth were determined. The grain growth kinetic parameters were compared with other magnesium alloys processed by various methods.

Diffusional Growth Kinetics of Boride Layers on Iron-Chromium Alloys

2008 ◽  
Vol 138 ◽  
pp. 181-188 ◽  
Author(s):  
Vasil I. Dybkov ◽  
L.V. Goncharuk ◽  
V.G. Khoruzha ◽  
K.A. Meleshevich ◽  
A.V. Samelyuk ◽  
...  
Keyword(s):  
Experimental Data ◽  
Growth Kinetics ◽  
Reaction Times ◽  
Layer Growth ◽  
Diffusional Growth ◽  
Chromium Alloys ◽  
Layer Growth Rate ◽  
Linear Differential ◽  
Kinetics Of ◽  
Iron Chromium

Two boride layers were found to form at the interface of iiron-chromiium alllloys (10 and 25% Cr) or an industrial 13% Cr steel and boron at 850-950 oC and reaction times in the range 1-12 h. In the case of a Fe-10% Cr alloy and the steel, the layers are based on the FeB and Fe2B compounds. With a Fe-25% Cr alloy, the constituent phases are FeB and CrB for the outer layer and Fe2B and Cr2B for the inner layer. Both layers are characterized by a pronounced texture. Diffusional growth kinetics of boride layers are close to parabolic and can alternatively be described by a system of two non-linear differential equations, producing a good fit to the experimental data. The temperature dependence of the layer growth-rate constants obeys a relation of the Arrhenius type.

Sign in / Sign up

Export Citation Format

Share Document