Study of Grain Growth Kinetics in Submicrocrystalline Armco-Iron

2007 ◽  
Vol 550 ◽  
pp. 465-470 ◽  
Author(s):  
A.N. Aleshin ◽  
Alex M. Arsenkin ◽  
Sergey V. Dobatkin
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Low Temperature ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Armco Iron ◽  
High Temperature Annealing ◽  
Grain Growth Kinetics ◽  
Submicrocrystalline Materials ◽  
Thermal Stability Of

The paper is devoted to the problem of thermal stability of ultra-fine grained (submicrocrystalline) materials prepared by severe plastic deformation. A basis of the paper lies in a fact that there is practically no grain growth in submicrocrystalline materials when annealing temperature is less than 0.35Tm. Reasons of high thermal stability of submicrocrystalline materials at low temperatures are widely discussed in literature. One of them is the affect of triple junction drag on grain boundaries motion. During annealing at a low temperature triple junction drag controls microstructure evolution in submicrocrystalline materials, and this phenomenon can be used to improve their thermal stability at high temperatures. The aim of this paper is to investigate grain growth kinetics in a two-step regime, low temperature and high temperature annealing. The experiments on grain growth were performed in submicrocrystalline Armco-iron fabricated by high pressure torsion. It is established that long-time low temperature pre-annealing reduces the grain growth rate in following high temperature annealing by a factor greater than two.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

scholarly journals Determination of Grain Growth Kinetics and Assessment of Welding Effect on Properties of S700MC Steel in the HAZ of Welded Joints

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 707 ◽  
Author(s):  
Jaromir Moravec ◽  
Iva Novakova ◽  
Jiri Sobotka ◽  
Heinz Neumann
Keyword(s):  
High Temperature ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Welded Joints ◽  
Material Constant ◽  
Temperature Cycle ◽  
Vacuum Furnace ◽  
Testing Procedures ◽  
Temperature Cycles ◽  
Grain Growth Kinetics

The welding of fine-grained steels is a very specific technology because of the requirement for the heat input limit value. Applying temperature cycles results in an intense grain growth in a high-temperature heat-affected zone (HAZ). This has a significant effect on the changing of strength properties and impact values. The intensity of grain coarsening in the HAZ can be predicted based on the experimentally determined activation energy and material constant, both of which define grain growth kinetics. These quantities, together with real measured welding cycles, can be subsequently used during experiments to determine mechanical properties in a high-temperature HAZ. This paper shows a methodical procedure leading to the obtainment of the material quantities mentioned above that define the grain growth, both at fast and slow temperature cycles. These data were used to define the exposure temperature and the soaking time in a vacuum furnace to prepare test samples with grain sizes corresponding to the high-temperature HAZ of welded joints for the testing procedures. Simultaneously, by means of the thermo-mechanical simulator Gleeble 3500, testing samples were prepared which, due to a temperature gradient, created conditions comparable to those in the HAZ. The experiments were both carried out with the possibility of free sample dilatation and under a condition of zero dilation, which happens when the thermal expansion of a material is compensated by plastic deformation. It has been found that shape of the temperature cycle, maximal achieved cycle temperature, cooling rate, and, particularly, the time in which the sample is in the austenite region have significant effects on the resulting change of properties.

Crystallization Characteristics and Thermal Stability of Fluor-Hydroxyapatite Composites with Zirconia

2012 ◽  
Vol 182-183 ◽  
pp. 122-125
Author(s):  
Li Li Wang ◽  
Xiu Feng Wang ◽  
Cheng Long Yu ◽  
Hong Tao Jiang
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Solid State ◽  
Low Temperature ◽  
Solid Solutions ◽  
Tricalcium Phosphate ◽  
Solid State Reaction ◽  
Calcium Fluoride ◽  
Raw Materials ◽  
Thermal Stability Of

Hydroxyapatite (HA) was synthesized in presence of 20wt% m-ZrO2by solid state reaction between tricalcium phosphate(TCP) and Ca(OH)2at 1000 °C for 2h. Similarily, Fluorine hydroxyapatite(FA) was synthesized using tricalcium phosphate and calcium fluoride as raw materials at 1000 °Cfor 3h. The as-prepared HA was mixed with 10%,25%,45%,55%,70wt% FA and the mixture was sintered at 1000°C-1400°C for 2h. The main phase and bulk density was measured. The results show that when the relative amount of FA to HA increased, the decomposition of the composite is decreased gradually because of the formation of thermally stable FHA solid solutions. Low temperature would effect the exchange of ionic between FA and HA,while high temperature would impact synthesis of composites, because high temperature would lead to dissolution of HA ,which has to react with FA. Increase the content of HA would be advantage for synthesis FHA-ZrO2composite.

Influence of Nitrogen Content on Thermal Stability and Grain Growth Kinetics of Cryomilled Al Nanocomposites

2011 ◽  
Vol 43 (2) ◽  
pp. 747-756 ◽  
Author(s):  
L. Hashemi-Sadraei ◽  
S. E. Mousavi ◽  
R. Vogt ◽  
Y. Li ◽  
Z. Zhang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nitrogen Content ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Grain Growth Kinetics ◽  
Kinetics Of

Thermal Stability and Grain Growth Kinetics of Ultrafine-Grained W with Various Amount of La2O3 Addition

2020 ◽  
Vol 51 (8) ◽  
pp. 4113-4122 ◽  
Author(s):  
Zheng Chen ◽  
Mingli Qin ◽  
Junjun Yang ◽  
Lin Zhang ◽  
Baorui Jia ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Ultrafine Grained ◽  
Grain Growth Kinetics ◽  
Kinetics Of

Improved thermal stability of a copper-containing ceria-based catalyst for low temperature CO oxidation under simulated diesel exhaust conditions

2018 ◽  
Vol 8 (5) ◽  
pp. 1383-1394 ◽  
Author(s):  
Iljeong Heo ◽  
Steven J. Schmieg ◽  
Se H. Oh ◽  
Wei Li ◽  
Charles H. F. Peden ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Low Temperature ◽  
Co Oxidation ◽  
Diesel Exhaust ◽  
Zirconium Oxide ◽  
Hydrothermal Aging ◽  
Remarkable Improvement ◽  
Low Temperature Co Oxidation ◽  
Thermal Stability Of

CuO supported on a commercial mixed cerium–zirconium oxide shows remarkable improvement in CO oxidation after high temperature hydrothermal aging.

Solid-State Reactions of SiC/W-25Re Alloy and Thermal Stability of SiC/Ti/W-25Re Alloy under High-Temperature Annealing

2016 ◽  
Vol 18 (9) ◽  
pp. 1574-1580
Author(s):  
Jun Sae Han ◽  
Seung Sik Jang ◽  
Dong Yong Park ◽  
Yong Jun Oh ◽  
Seong Jin Park
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Solid State ◽  
Solid State Reactions ◽  
High Temperature Annealing ◽  
Thermal Stability Of

scholarly journals Comprehensive microstructural and optical characterization of the thermal stability of aluminum-titanium oxynitride thin films after high temperature annealing in air

2021 ◽  
Author(s):  
R. Escobar-Galindo ◽  
I. Heras ◽  
E. Guillén ◽  
F. Munnik ◽  
I. Azkona ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Stability ◽  
High Temperature ◽  
Dielectric Behavior ◽  
Vacuum Arc ◽  
Surface Oxide Layer ◽  
High Temperature Annealing ◽  
Elastic Recoil ◽  
Thermal Stability Of

AbstractThe thermal stability of two AlyTi1-y(OxN1-x) layers prepared by cathodic vacuum arc deposition with different oxygen content was studied after high temperature annealing of the samples in air. These layers were designed to be part of solar-selective coating (SSC) stacks. Compositional and microstructural characterization of the thin films was performed before and after the thermal treatment by elastic recoil detection (ERD), transmission electron microscopy, and Raman spectroscopy. AlyTi1-yN sample was stable after 2 h of annealing at 450 °C. Initial stages of the formation of a surface oxide layer after annealing at 650 °C were observed both by ERD and Raman analysis. Contrarily, no changes were found after 2 h annealing treatment either at 450 and 650 °C in the composition and microstructure of AlyTi1-y(OxN1-x) sample. In both samples, the formation of a surface anatase TiO2 film was reported after 2 h annealing at 800 °C. These compositional and microstructural changes were correlated with the optical properties determined by spectroscopic ellipsometry. A transition from metallic to dielectric behavior with increasing annealing temperature was observed. These results complete the durability studies on the designed SSC based on AlyTi1-y(OxN1-x) materials, confirming that these stacks withstand breakdown at 600 °C in air.

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