High-temperature corrosion of Ti and Ti-6Al-4V alloy

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Oxidation of Metals

DOI:https://doi.org/10.1007/BF01046849· OSTI ID:283041

Du, H L; Datta, P K; Burnell-Gray, J S ^[1]; Lewis, D B ^[2]

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1. Univ. of Northumbria, Newcastle (United Kingdom)
2. Sheffield Hallam Univ. (United Kingdom)

Pure titanium and Ti-6Al-4V were exposed at 750{degrees}C in an H{sub 2}/H{sub 2}O/H{sub 2}S (P{sub O{sub 2}} {approximately} 10{sup {minus}18} Pa and P{sub S{sub 2}}{approximately} 10{sup {minus}1}Pa), H{sub 2}/H{sub 2}O (P{sub O{sub 2}}{approximately} 10{sup {minus}18} Pa) and air environments for up to 240 hr. The corrosion kinetics, obtained by the discontinuous gravimetric method, showed that the sulfidation/oxidation kinetics were linear for Ti and linear-parabolic for Ti-6Al-4V in the H{sub 2}/H{sub 2}O atmosphere after a transient period, and linear-parabolic rate laws in air. After exposure to the H{sub 2}/H{sub 2}O/H{sub 2}S atmosphere, the titanium specimen displayed a double scale of TiO{sub 2} and the substrate. Ti-6Al-4V also contained a double layer of TiO{sub 2} together with a stratum consisting of Al{sub 2}S{sub 3}, TiS{sub 2} and vanadium sulfide at the junction of the inner TiO{sub 2} layer and substrate. Some Al{sub 2}O{sub 3} precipitated in the external portion of the outer TiO{sub 2} layer. Following oxidation in the low-P{sub O{sub 2}} atmosphere a double-layered oxide of TiO{sub 2} scale formed on both Ti and Ti-6Al-4V. The scale on Ti-6Al-4V also contained an {alpha}-Al{sub 2}O{sub 3} film situated between the outer and inner (TiO{sub 2}) layers. For both materials, multilayered-scale formation characterized air oxidation. In detail a multilayered oxide scale of TiO{sub 2} formed on the air-oxidized Ti, while a multilayered oxide scale with alternating layers of Al{sub 2}O{sub 3}/TiO{sub 2} developed on Ti-6Al-4V oxidized in air.

• Sponsoring Organization: USDOE
• OSTI ID: 283041
• Journal Information: Oxidation of Metals, Journal Name: Oxidation of Metals Journal Issue: 5-6 Vol. 45; ISSN OXMEAF; ISSN 0030-770X
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CORROSION
HYDROGEN
HYDROGEN SULFIDES
SCALING
TEMPERATURE RANGE 1000-4000 K
TITANIUM
TITANIUM BASE ALLOYS
VANADIUM ALLOYS
WATER VAPOR