Predicting the Parabolic Rate Constants of High-Temperature Oxidation of Ti Alloys Using Machine Learning

2020 ◽  
Vol 94 (3-4) ◽  
pp. 205-218
Author(s):  
Somesh Kr. Bhattacharya ◽  
Ryoji Sahara ◽  
Takayuki Narushima
Keyword(s):  
Machine Learning ◽  
High Temperature ◽  
Rate Constants ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Ti Alloys ◽  
Parabolic Rate ◽  
Parabolic Rate Constants

scholarly journals Additively Manufactured NiTi and NiTiHf Alloys: Estimating Service Life in High-Temperature Oxidation

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2104 ◽  
Author(s):  
Hediyeh Dabbaghi ◽  
Keyvan Safaei ◽  
Mohammadreza Nematollahi ◽  
Parisa Bayati ◽  
Mohammad Elahinia
Keyword(s):  
High Temperature ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Early Stage ◽  
Niti Alloy ◽  
Temperature Oxidation ◽  
X Ray ◽  
Rate Law ◽  
Parabolic Rate

In this study, the effect of the addition of Hf on the oxidation behavior of NiTi alloy, which was processed using additive manufacturing and casting, is studied. Thermogravimetric analyses (TGA) were performed at the temperature of 500, 800, and 900 °C to assess the isothermal and dynamic oxidation behavior of the Ni50.4Ti29.6Hf20 at.% alloys for 75 h in dry air. After oxidation, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to analyze the oxide scale formed on the surface of the samples during the high-temperature oxidation. Two stages of oxidation were observed for the NiTiHf samples, an increasing oxidation rate during the early stage of oxidation followed by a lower oxidation rate after approximately 10 h. The isothermal oxidation curves were well matched with a logarithmic rate law in the initial stage and then by parabolic rate law for the next stage. The formation of multi-layered oxide was observed for NiTiHf, which consists of Ti oxide, Hf oxide, and NiTiO3. For the binary alloys, results show that by increasing the temperature, the oxidation rate increased significantly and fitted with parabolic rate law. Activation energy of 175.25 kJ/mol for additively manufactured (AM) NiTi and 60.634 kJ/mol for AM NiTiHf was obtained.

scholarly journals High Temperature Oxidation Behaviors of CrNx and Cr-Si-N Thin Films at 1000 °C

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 540 ◽  
Author(s):  
Bih-Show Lou ◽  
Yue-Chyuan Chang ◽  
Jyh-Wei Lee
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Oxide Layer ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Oxidation Test ◽  
Parabolic Rate ◽  
Oxidation Behaviors

The high temperature oxidation performance of nitride thin films has become an important issue when they are used as protective coatings on dry cutting tools or on die casting molds. In this study, the high temperature oxidation behaviors of CrNx and Cr-Si-N thin films were investigated at 1000 °C for 6 h in ambient air. The CrNx and Cr-Si-N thin films were prepared by a bipolar asymmetric pulsed direct-current (DC) magnetron sputtering system. Cr-Si-N films with silicon content ranging from 3.9 to 12.2 at.% were deposited by adjusting the Si target power. A thermogravimeter was adopted to study the oxidation kinetics of thin films. The weight gains were measured to calculate the parabolic rate constants of thin films. X-ray diffraction, X-ray mapping, and Auger electron spectroscopy were employed to study the microstructure and elemental redistributions of oxidized thin films. The as-deposited CrNx and Cr-Si-N thin films consisted of CrN and Cr2N mixed phases. The faceted Cr2O3 surface oxides, porous inner oxide layer, and oxygen-containing CrSi2 phases were found for the CrN film after oxidation test. On the other hand, the Cr-Si-N film containing 12.2 at.% Si showed a dense surface oxide layer and a thick and compact nitride layer, which indicates its best oxidation resistance. The high temperature oxidation resistance of Cr-Si-N thin films was improved by increasing Si content, due to the amorphous matrix contained nanocomposite microstructure and the formation of amorphous silicon oxide to retard the diffusion paths of oxygen, chromium, silicon, and nitrogen. The lowest parabolic rate constant of 1.48 × 10–2 mg2/cm4/h was obtained for the 12.2 at.% Si contained Cr-Si-N thin films, which provided the best oxidation resistance at 1000 °C for 6 h in this work. It should be noted that the residual tensile stress of thin film had a detrimental effect on the adhesion property during the oxidation test.

Effect of Yttrium Addition on High Temperature Oxidation Resistance of Co-10Cr-5Al Alloys

2011 ◽  
Vol 391-392 ◽  
pp. 606-610 ◽  
Author(s):  
Huai Shu Zhang ◽  
Hong Hua Zhang ◽  
Jun Huai Xiang ◽  
Shan Wang ◽  
Di Wu
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Oxidation Rate ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Temperature Oxidation ◽  
Linear Rate ◽  
Rate Law ◽  
Yttrium Addition ◽  
Parabolic Rate

The oxidation behavior of Co-10Cr-5Al-0.3Y alloy in 1 atm of pure O2 at 700°C was investigated. The addition of 0.3 at.%Y significantly increased the oxidation rate of the alloy and changed the oxidation behavior from the approximate parabolic rate law to linear rate law. The scale grown on the surface at 700°C was porous with many small voids and cracks, and was composed of an outer CoO layer and an inner complex layer rich in Al2O3 and Cr2O3 which were intermingled with yttric oxide and spinel Co(Cr, Al)2O4.

Design of near-α Ti alloys via a cluster formula approach and their high-temperature oxidation resistance

2019 ◽  
Vol 35 (6) ◽  
pp. 1008-1016 ◽  
Author(s):  
Beibei Jiang ◽  
Donghui Wen ◽  
Qing Wang ◽  
Jinda Che ◽  
Chuang Dong ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Ti Alloys

High-Temperature Sulfidation of Crofer 22APU in Atmospheres Containing H2S and H2O

2011 ◽  
Vol 347-353 ◽  
pp. 3321-3324
Author(s):  
Zbigniew Żurek ◽  
Artur Jaron ◽  
Aleksander Gil
Keyword(s):  
High Temperature ◽  
Rate Constants ◽  
Oxidation Rate ◽  
Oxidation Process ◽  
Hydrogen Atmosphere ◽  
Parabolic Law ◽  
Steel Oxidation ◽  
Parabolic Rate ◽  
Parabolic Rate Constants ◽  
Periodic Method

The work presents analyses of Crofer 22APU steel oxidation in hydrogen atmosphere containing 300 ppm H2S and in hydrogen atmosphere containing 300 ppm and 1% H2O. The oxidation process was conducted on two kinds of samples: pre-oxidized (pre-oxidation process was carried out in the air at a temperature of 800°C during 100 h), and not pre-oxidized at a temperature of 600 and 800°C using periodic method during 500 h. It was established that oxidation rate may be described by means of parabolic law. Determined parabolic rate constants indicate that not pre-oxidized samples undergo sulphurization in H2/300ppm H2S atmosphere, while in H2/300ppm H2S + 1%H2O atmosphere they undergo oxidation 3-4 orders of magnitude slower.

High Temperature Oxidation of Bond Coats in Thermal Barrier Systems

1998 ◽  
Author(s):  
R. Peraldi ◽  
D. Monceau ◽  
B. Pieraggi ◽  
A. Malie
Keyword(s):  
Rate Constants ◽  
Low Oxygen ◽  
Heating Rates ◽  
Temperature Oxidation ◽  
Bond Coats ◽  
Parabolic Kinetics ◽  
Mcraly Coatings ◽  
Partial Pressures ◽  
Parabolic Rate ◽  
Parabolic Rate Constants

Abstract The isothermal oxidation of bond coats composed of vacuum plasma sprayed (VPS) MCrAlY (NiCoCrAlYTa and CoNiCrAlY) or palladium modified nickel aluminides (NiPd + APVS) was studied in several oxygen partial pressures (105, 1 and 10-5 Pa), with two heating rates (20 and 60K/min) at different temperatures (900, 1000 and 1100°C). For MCrAlY coatings, Arrhenius plots of the parabolic rate constants show a kinetic transition below 1000°C. This could be linked to a transition from Al2O3 to Cr2O3 scale growth. Lower oxygen partial pressures induce lower parabolic rate constants at 900°C. This leads to the assumption that scales grown at low oxygen partial pressures are still formed of alumina at 900°C. Nevertheless, these results could not be confirmed by chemical analysis (EDS, XPS). The two tested heating rates show no influence on the oxidation kinetics of both MCrAlY coatings. In the case of aluminide, for low oxygen partial pressures, the parabolic kinetics are reduced of one order of magnitude (for PO2 =105 to 1 Pa) and correspond to a thinner scale of a-alumina. Also, the heating rate modifies the parabolic kinetics (i.e. after the transient stage) and the total weight gains for all oxidation temperatures, with higher parabolic rate constants after heating at slower rate.

Sign in / Sign up

Export Citation Format

Share Document