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4 results on '"micromechanical tensile testing"'

1. Effect of oxygen content on the sub-grain nanoindentation response in titanium affected by high temperature oxidation

Author

Texier, Damien, Sirvin, Quentin, Dziri, Ayyoub, Proudhon, Henry, Yastrebov, Vladislav, Legros, Marc, Institut Clément Ader (ICA), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre des Matériaux (CDM), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Physique de la Plasticité et Métallurgie (CEMES-PPM), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and European Project: 948007,HT-S4DefOx

Subjects
Commercial pure titanium, [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph], mechanical behavior, micromechanical tensile testing, oxygen embrittlement, gradient of properties
Abstract

International audience; Pre-oxidation tests were performed on a commercially pure titanium (CP-40) at 700 °C for 100 h under air in order to introduce a gradient of oxygen content within the metal, also called the oxygen-rich layer (ORL). The chemical profile of oxygen was measured using microprobe analyses (EPMA) on cross-sectional observations. Large but highly resolved nanoindentation maps using continuous stiffness measurement techniques were performed on the specimen cross-section to document the local mechanical response within the oxygen-rich layer (ORL) as a function of the oxygen content and the grain orientation using statistical and multi-modal analyses. The oxygen was found to greatly increase the hardness and elastic modulus in titanium and was correlated to orientation of the c axis of the α-Ti.

Published
2023

2. Oxygen content effect on mechanical behaviour of cp titanium exposed at elevated temperature

Author

Sirvin, Quentin, Texier, Damien, Velay, Vincent, Monceau, Daniel, Dod, Benjamin, Institut Clément Ader (ICA), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Airbus [France], and ANR-18-CE08-0003,COMPAACT,Etude du couplage ' corrosion-oxydation-comportement mécanique ' par des techniques de caractérisation avancées(2018)

Subjects
Commercial pure titanium, [SPI.MECA.MEMA]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanics of materials [physics.class-ph], micromechanical tensile testing, oxygen embrittlement, gradient of properties, mechanical behaviour
Abstract

International audience; Ti-based alloys are particularly prone to oxygen dissolution and embrittlement. Oxygen solubility within titanium leads to the formation of an oxygen-diffusion zone (ODZ) during oxidation processes for a depth up to ten times thicker than the oxide layer. The mechanical and oxidation behaviour of the CP-Ti was investigated using micro-tensile testing of 50 to 800 μm-thick pre-oxidized specimens. Pre-oxidation treatments at 700 °C with various exposures have been performed to generate different ODZ thickness/non-affected material (NAM) thickness ratios ranging from 0 to 100%. These investigations aimed to identify the competition between strengthening effects due to oxygen enrichment and the damage development due to oxygen embrittlement using the graded-property material structure composed of different percentages of NAM and ODZ. Mechanical properties of CP-Ti rise with oxidation time except for strain to failure. The extension of the ODZ follow parabolic law with a parabolic constant 20 μm².h-1.

Published
2023

3. Oxygen/nitrogen-assisted embrittlement of titanium alloys exposed at elevated temperature

Author

Texier D., Sirvin Q., Velay V., Salem M., Monceau D., Mazères B., Andrieu E., Roumiguier R., and Dod B.

Subjects
titanium alloy, micromechanical tensile testing, oxidation, oxygen diffusion, oxygen embrittlement, Engineering (General). Civil engineering (General), TA1-2040
Abstract

Due to high solubility of oxygen and nitrogen in titanium alloys, the influence of the diffusion zone on the macroscopic tensile properties of pre-oxidized annealed Ti-6Al-4V tensile specimens was examined at room temperature. Thin microtensile specimens were prepared with different thicknesses ranging from 100 µm to 500 µm and then exposed at 750°C for durations between 5 and 200h. A dedicated gripping technique was developed in the present study to investigate the brittleness of such pre-oxidized and ultrathin specimens at room temperature. Tensile testing was paired with digital image correlation techniques to assess both macroscopic deformation and full-field strain maps. High temperature pre-oxidation treatments significantly decreased the ductility of the specimen and the tensile strength of the materials (yield strength and ultimate tensile strength). Fractographic examinations revealed typical brittle fracture features in the oxygen/nitrogen-affected diffusion zone in the periphery of the cross-section while the fracture remained ductile in the core of the specimen for most of the specimens. Some specimens fully failed in a brittle manner for “(pre-ox. duration)1/2/thickness” configurations with ratio equal or higher than 0.45 h1/2.µm-1.

Published
2020
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4. Oxygen/nitrogen-assisted degradation of the mechanical behavior of titanium alloys exposed at elevated temperature

Author

Texier, Damien, Sirvin, Q., Velay, Vincent, Mehdi SALEM, Monceau, Daniel, Mazères, Benoît, Andrieu, Eric, Roumiguier, Rémi, Dod, Benjamin B., Institut Clément Ader (ICA), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), MIDIVAL, AIRBUS Operations Ltd., Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-IMT École nationale supérieure des Mines d'Albi-Carmaux (IMT Mines Albi), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)

Subjects
Titanium, Oxygen diffusion, Micromechanical tensile testing, Oxygen solubility, Oxygen embrittlement, [SPI.MAT]Engineering Sciences [physics]/Materials, Brittle and ductile deformation, [PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], [SPI]Engineering Sciences [physics], Oxidation, Digital image Correlation, Tensile Behavior, Titanium alloy, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Brittle Fracture
Abstract

International audience; Titanium alloys are increasingly used in the manufacture of intermediate/high temperature structural components. In service, these components are exposed to elevated temperatures (T> 300°C up to 650°C) and oxidative/nitriding atmospheres, typically the air. However, titanium and titanium alloys are particularly prone to substantial oxygen and nitrogen solubility (ex: up to 33% at. for O and 9.6 % at. for N in the alpha phase at 650°C). Therefore, this chemical solubility leads to element partition during high temperature oxidation/nitridation and thus to the formation of an oxygen/nitrogen-affected diffusion zone (ONADZ) for depths at least one order of magnitude thicker than the oxide layer. Due to the brittleness of the ONADZ, this zone strongly impairs the mechanical integrity of Ti-alloys structural components subjected to mechanical loading and thermal exposure, especially for cyclic stresses [1-2]. The ONADZ fails in a brittle manner and transverse cracks develop on the whole gauge section, acting as severe notches in service conditions. Therefore, assessing the local mechanical behavior of the ONADZ and predicting its early cracking in various stress amplitude/temperature ranges are central problematics to better implement microstructure-based fatigue criteria in structural design of Ti-alloys components. In the present study, the mechanical behavior of the ONADZ is investigated using tensile testing of ultrathin pre-oxidized specimens. Ultrathin specimens exhibit a substantial surface/volume ratio that is interestingly appropriate for the study of surface reactivity, i.e. oxidation, nitridation. 65-µm thick specimens were prepared using a precision Jig polishing technique detailed in ref [3]. Preoxidation treatments at 750°C with various high temperature exposure durations have been performed in order to generate different ONADZ thicknesses. Room temperature (RT) tensile testing of the pre-oxidized specimens paired with a two-scale digital image correlation (DIC) technique. This allows an investigation of: (i) the macroscopic stress/strain response of the composite structure made of a non-affected core region surrounded by the ONADZ, (ii) irreversible deformation/cracking events at the microstructure scale as a function of the ONADZ thickness. RT tensile tests on pre-oxidized Ti6242 specimens demonstrated the feasibility of such micromechanical testing adapted to Ti alloys. Increasing the pre-oxidation time at a given temperature leads to a considerable drop of the ductility, the 750°C-24h pre-oxidized specimen being fully brittle. Fracture surface observations outline the extension as a function of the pre-oxidation duration and the brittle behavior of the ONADZ (Figure 1). Figure 1: Fracture surface of pre-oxidized specimens after RT tensile testing: a) non-oxidized specimen, b) 750°C-2h pre-oxidation treatment, c) 750°C-24h pre-oxidation treatment. References: [1] C.E. Shamblen, T.K. Redden, Air contamination and embrittlement in titanium alloys, The Science, Technology, and Application of Titanium, Pergamon Press, (1968) 199–208. [2] T.A. Parthasarathy, W.J. Porter, S. Boone, R. John and P. Martin, Life prediction under tension of titanium alloys that develop an oxygenated brittle case during use, Scripta Mater. 65 (2011) 420–423. [3] D. Texier, D. Monceau, J.-C. Salabura, R. Mainguy, E. Andrieu, Micromechanical testing of ultrathin layered material specimens at elevated temperature, Mater. High Temp. 33 (2016) 325–337.

Published
2019
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