Effect of hydrogen on the behavior of metals. II. Hydrogen embrittlement of titanium alloy TV13CA: effect of oxygen comparison with nonalloyed titanium

Technical Report · Thu Nov 01 04:00:00 EST 1973

OSTI ID:4937346

Arditty, J P

The effects of oxygen on hydrogen embrittlement of nonalloyed titanium and the metastable BETA -titanium alloy, TV13CA, were studied duting dynamic mechanical tests, the concentrations considered varying from 1000 to 5000 ppM (oxygen) and from 0 to 5000 ppM (hydrogen) respectively. TV13CA alloy has a very high solubility for hydrogen. The establishment of a temperature rang; and a rate of deformation region in which the embrittlement of the alloy is maximum leads to the conclusion that an embrittlement mechanism occurs involving the dragging and accumulation of hydrogen by dislocations. This is the case for all annealings effected in the medium temperature range, which, by favoring the re- establishment of the stable two-phase alpha + BETA state of the alloy, produce hardening. The same is true for oxygen which, in addition to hardening the alloy by solid-solution effects, tends to increase its instability and, in consequence, favors the decomposition of the BETA phase. Oxygen concentrations of up to 1500 ppM contribute to increasing the mechanical resistance without catastrophically reducing the deformation capacity. In the case of nonalloyed titanium, the hardening effect also leads to an increase In E/sub 0.2% and R, and to a reduction in the deformation capacity. Hydrogen is only very slightly soluble at room temperature, and a distribution of the hydride phase linked to the thermal history of the sample predominates. Thus, a fine acicular structure obained from the BETA phase by quenching enables an alloy having a good mechanical resistance to be conserved even when large uantities of hydrogen are present; the deformation capacity remains small. When the hydride phase separates the metallic phase into large grains, a very small elongation leads to a breakdown in mechanical resistance. (auth)

• Research Organization: CEA Centre d'Etudes de Bruyeres-le-Chatel, 92 - Montrouge (France)
• Sponsoring Organization: Sponsor not identified
• NSA Number: NSA-29-017999
• OSTI ID: 4937346
• Report Number(s): CEA-R--4528
• Country of Publication: France
• Language: French

Related Subjects

CHEMICAL COMPOSITION
CHEMICAL REACTIONS
DEFORMATION
DIFFUSION
EMBRITTLEMENT
HARDENING
HYDRIDES
HYDROGEN
N50230 -- Metals
Ceramics
& Other Materials--Metals & Alloys--Properties
Structure & Phase Studies
N80730* --General & Miscellaneous--Materials
OXIDES
OXYGEN
SOLUBILITY
TITANIUM
TITANIUM BASE ALLOYS