Modelling High Temperature Oxidation in Iron–Chromium Systems: Combined Kinetic and Thermodynamic Calculation of the Long-Term Behaviour and Experimental Verification

Titanium alloys, such as Ti-6Al-4V alloy, fabricated by additive manufacturing processes is a winning combination in the aeronautic field. Indeed, the high specific mechanical properties of titanium alloys with the optimized design of parts allowed by additive manufacturing should allow aircraft weight reduction. But, the long term use of Ti-6Al-4V alloy is limited to 315 °C due to high oxidation kinetics above this temperature [1]. The formation of an oxygen diffusion zone in the metal and an oxide layer above it may reduce the durability of titanium parts leading to premature failure [2, 3]. In this study, Ti-6Al-4V alloy was fabricated by Electron Beam Melting (EBM). As built microstructure evolutions after Hot Isostatic Pressure (HIP) treatment at 920 °C and 1000 bar for 2h were investigated. As built microstructure of Ti-6Al-4V fabricated by EBM was composed of Ti-α laths in a Ti-β matrix. High temperature oxidation of Ti-6Al-4V alloy at 600 °C of as-built and HIP-ed microstructures was studied. This temperature was chosen to increase oxidation kinetics and to study the influence of oxidation on tensile mechanical properties. In parallel, two other oxidation temperatures, i.e. 500 °C and 550°C allowed to access to the effect of temperature on long-term oxidation.

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Detailed electrical and mechanical retention characteristics of MoSi2–RSiC composites exhibiting three-dimensional (3D) interpenetrated network structure during long-term high-temperature oxidation process

Ceramics International ◽

10.1016/j.ceramint.2015.12.131 ◽

2016 ◽

Vol 42 (5) ◽

pp. 5873-5884 ◽

Cited By ~ 6

Author(s):

Wen Xie ◽

Peng-zhao Gao ◽

Dong-yun Li ◽

Hua-nan Lv ◽

Shi-ting Huang ◽

...

Keyword(s):

High Temperature ◽

Network Structure ◽

High Temperature Oxidation ◽

Oxidation Process ◽

Three Dimensional ◽

Temperature Oxidation ◽

Retention Characteristics

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Arc-Spraying Composite Coatings on Mild Steel for Long-Term High-Temperature Oxidation Protection

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.690-693.2039 ◽

2013 ◽

Vol 690-693 ◽

pp. 2039-2045

Author(s):

Zhong Li Zhang ◽

Qi Shen Wang ◽

Peng Rao Wei ◽

Xue Gong

Keyword(s):

High Temperature ◽

High Temperature Oxidation ◽

Protective Coatings ◽

Steel Substrate ◽

Composite Coatings ◽

Arc Spraying ◽

Al Alloy ◽

Temperature Oxidation ◽

Oxidation Protection

An arc-spraying composite coating system for high-temperature oxidation protection is composed of an inner Fe-Cr-Al alloy layer and an Al-Si alloy outer layer. The high-temperature oxidation behavior of the composite coatings on steel substrate was studied during isothermal exposures in air at 900°C. Experiments show that the coatings on steel substrate are not deteriorated and the substrate is protected well, being exposed to high temperatures up to 900°C. Inter diffusion of alloying elements within the protective coatings occur, while the elements, Cr and Al, are also diffusing to the core of the base metal. As test time proceeds, a large number of chromium oxides are generated in situ within the protective coatings, especially close to the coating/substrate interface. The oxides generated increase the bond strength of the coating to the steel substrate, and together with the surface alumina they provide a long-term effective anti-oxidant protection to steel substrate. The results on titanium sponge production site show that the protective coatings on the reactor have provided an effective protection and prolong the lifetime at least forty percent for the reactors.

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