High Temperature Oxidation of TiAl-1.5wt.%Mn-(0, 5, 10)wt.%Y2O3 Alloys

TiAl-Mn-(0,5,10) wt.%Y2O3 alloys were prepared by the MA-SPS process, and their oxidation behavior was studied between 800 and 1000oC in 1 atm of air. The added Y2O3 particles were segregated along the matrix grain boundaries. The addition of (5~10) wt.%Y2O3, viz. (0.9~1.8) mol%Y2O3 increased the tendency to form the rutile phase along the grain boundaries, resulting in the increment of the oxidation rate and decrement of scale adherence. Mn was oxidized to Mn2O3. The primary mode of scale growth was the outward diffusion of Ti and Mn cations for the outer TiO2 scale, and the inward transport of oxygen anions for the inner (TiO2+Al2O3) mixed scale.

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Influence Mechanism of Cu on High Temperature Oxidation Behavior of Titanium Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.944.110 ◽

2019 ◽

Vol 944 ◽

pp. 110-119 ◽

Cited By ~ 1

Author(s):

Hang Chen ◽

Guang Bao Mi ◽

Pei Jie Li ◽

Chun Xiao Cao

Keyword(s):

High Temperature ◽

Grain Boundaries ◽

Oxide Layer ◽

High Temperature Oxidation ◽

Oxidation Behavior ◽

Temperature Oxidation ◽

Oxidation Rates ◽

Cu Alloy ◽

Cu Alloys ◽

Oxidation Surface

The oxidation behavior and mechanism of Ti-Cu alloys (0≤w(Cu)≤20%) in the temperature range of 1000°C～1300°C are studied by thermogravimetric analysis(TGA) combined with SEM, EDS and XRD analysis methods. The results show that the oxidation rates of Ti-Cu alloys increase sharply when the temperature rises above 1000°C. The oxidation products have a three-layer structure, from the outside to the inside, which are dense outer oxide layer of TiO2, porous inner oxide layer of low valence oxide of Ti and Cu-enriched layer. With the increase of the temperature, the thicknesses of oxide layers of Ti-Cu alloy increase and the Cu-enriched phase increases gradually and melts. The melting Cu-enriched phase flows to the oxidation surface along the grain boundaries of the oxide layer. The high temperature oxidation resistance of Ti-Cu alloys declines with the increase of Cu content. The main reason is that more liquid Cu-enriched phase is formed and flows to the oxidation surface along the oxide grain boundaries in the Ti-Cu alloy, and Ti and O ions can diffuse more easily along the liquid Cu-enriched phase, which increases the oxidation rates.

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High Temperature Oxidation Behavior of an Equimolar Cr-Mn-Fe-Co High-Entropy Alloy

Materials ◽

10.3390/ma14154259 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4259

Author(s):

Lin Wang ◽

Quanqing Zeng ◽

Zhibao Xie ◽

Yun Zhang ◽

Haitao Gao

Keyword(s):

High Temperature ◽

Oxide Layer ◽

High Temperature Oxidation ◽

Oxidation Behavior ◽

High Entropy Alloy ◽

Spinel Type ◽

Temperature Oxidation ◽

Outward Diffusion ◽

High Entropy ◽

High Temperature Oxidation Behavior

The oxidation behavior of an equimolar Cr-Mn-Fe-Co high-entropy alloy (HEA) processed by 3D laser printing was investigated at 700 °C and 900 °C. The oxidation kinetics of the alloy followed the parabolic rate law, and the oxidation rate constant increased with the rising of the temperature. Inward diffusion of oxygen and outward diffusion of cations took place during the high-temperature oxidation process. A spinel-type oxide was formed on the surface, and the thickness of the oxide layer increased with the rising of experimental temperature or time. The exfoliation of the oxide layer took place when the test was operated at 900 °C over 12 h. During oxidation tests, the matrix was propped open by oxides and was segmented into small pieces. The formation of loose structures had great effects on the high-temperature oxidation resistance of the HEA.

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High-Temperature Oxidation Behavior of Fe–1Cr–0.2Si Steel

Materials ◽

10.3390/ma13030509 ◽

2020 ◽

Vol 13 (3) ◽

pp. 509

Author(s):

Mingxin Hao ◽

Bin Sun ◽

Hao Wang

Keyword(s):

High Temperature ◽

Iron Oxide ◽

High Temperature Oxidation ◽

Oxidation Behavior ◽

Steel Tube ◽

Temperature Oxidation ◽

Outward Diffusion ◽

High Temperature Oxidation Behavior ◽

Mixed Layers ◽

Oxidation Weight Gain

In the case of Fe–1Cr–0.2Si steel, tube furnace oxidation was carried out for 120 min and 30 min. These studies, along with the high-temperature oxidation behavior of Fe–1Cr–0.2Si steel, were examined from 700 to 1100 °C. It has been observed that with an increase in the oxidation time, the oxidation weight gain per unit area of Fe–1Cr–0.2Si steel changed from a linear to a parabolic relationship. The time was shortened when the oxidation phase was linear. When the oxidation temperature exceeded 900 °C, the value of WTransition decreased, and the oxidation rule changed. It could be considered that overall, the iron oxide structure of Fe–1Cr–0.2Si steel is divided into two layers. The formation of an outer oxide of iron is mainly caused by the outward diffusion of cation, while the inward diffusion of O ion forms the inner oxides of chromium and silicon. As the temperature increases, the thickness of the outer iron oxide gradually increases, and the thickness ratio of the inner mixed layers of chromium- and silicon-rich oxides decreases; however, the degree of enrichment of Cr and Si in the mixed layer increases. After high-temperature oxidation, Cr and Si did not form a composite oxide but were mechanically mixed in the form of FeCr2O4 and Fe2SiO4, and no significant delamination occurred.

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