Geoffrey Ringot

French Corrosion Institute

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Flavien Vucko

French Corrosion Institute

Maxime Dumouchel

Centre Hospitalier Régional Universitaire de Brest

José María Cabrera

Universitat Politècnica de Catalunya

Lallie Duval

French Corrosion Institute

Nicolas Larché

French Corrosion Institute

Michel Prestat

French Corrosion Institute

Lorenz Holzer

ZHAW Zurich University of Applied Sciences

Terence G. Langdon

University of Southern California

Anne Le Gac

French Corrosion Institute

Alexander P. Zhilyaev

Institute of Metal Superplasticity Problems

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French Corrosion Institute

University of Southampton

RISE Research Institutes of Sweden

Centre National de la Recherche Scientifique

Universitat Politècnica de Catalunya

Fundació CTM Centre Tecnològic

ZHAW Zurich University of Applied Sciences

Swiss Federal Laboratories for Materials Science and Technology

Paul Scherrer Institute

Computational Physics (United States)

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Fatigue Behavior of Super Duplex Stainless Steel Exposed in Natural Seawater Under Cathodic Protection

Frontiers in Materials (2022)

Flavien Vucko Geoffrey Ringot Dominique Thierry Nicolas Larché

Under operating conditions, alternated loading and fatigue are encountered, controlling the durability and safety of components and structures made of super duplex stainless steel (SDSS). In particular, the use of a cathodic protection (CP) system to protect the structure against corrosion can induce hydrogen charging of the SDSS. Thus, the aim of this study was to investigate the sensitivity of some industrial products made of SDSS 2507 (UNS S32750), without artificial thermal aging, under test conditions as close as possible to real environments. In situ fatigue tests under alternated 4-point bending conditions were conducted in natural seawater with and without CP. The fatigue behavior was evaluated as a function of environmental parameters, such as temperature, and material parameters, particularly the austenite spacing and microstructure around orbital welds by Tungsten Inert Gas (TIG) welding and stress concentrations, through the presence of surface defects. The fatigue life obtained in air or in seawater at the open circuit potential (OCP) was rather similar. Fatigue life enhancement was systematically observed under CP particularly in the range of low applied load, despite evidence of brittle failure on the fracture surfaces of samples tested under CP. The data suggest immunity of the SDSS to hydrogen embrittlement under the present experimental conditions of fatigue testing.

Corrosion Fatigue

Artificial seawater

Galvanic anode

Embrittlement

10.3389/fmats.2022.826189

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Mechanical behavior and microstructure properties of titanium powder consolidated by high-pressure torsion

Materials Science and Engineering A (2017)

Alexander P. Zhilyaev Geoffrey Ringot Yi Huang José María Cabrera Terence G. Langdon

Severe Plastic Deformation

10.1016/j.msea.2017.02.032

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Citations (57)

Electrochemical, Microstructural and Mechanical Investigations of H₂O₂-Driven Degradation of Ti6Al4V

Meeting abstracts/Meeting abstracts (Electrochemical Society. CD-ROM) (2023)

Michel Prestat Geoffrey Ringot Lallie Duval Anne Le Gac Lorenz Holzer

Titanium and its alloys consitute one of the main classes of materials utilized as non-biodegradable implants in the human body. The corrosion resistance of titanium is mainly due to the presence of a thin, compact and passive layer on its surface. However, this layer degrades in the presence of reactive oxygen species, such as oxygen peroxide (H 2 O 2 ) [1,2]. This leads to the device degradation and the release of its constituents in the surrounding tissues, which may bring about serious health issues (peri-implantitis, osteolysis, neurotoxicity...) [3]. H 2 O 2 is produced by the immune system during inflammatory episodes by specific enzymes, such as NADPH oxidase and superoxide dismutase [4]. It is also utilized by surgeons at high concentrations (ca. 1 M) during peri-implant tissue disinfection. Ti6Al4V (titanium grade 5, an α + β alloy) is a popular implant material because of its excellent mechanical properties. However, in recent years, Ti6Al4V with equiaxed α grains (and β phase located at the grain boundaries) was reported to undergo a significant degradation by H 2 O 2 characterized by the growth of a thick oxide layer on the α grains and the development of porosity and cracks in the β phase [1]. Ti6Al4V could be susceptible to stress corrosion cracking (SCC) under mechanical load due to the β phase dissolution in H 2 O 2 -containing physiological solutions (Figure 1). However, no clear link has been established yet between the corrosive environment, the mechanical load and the microstructure of the Ti6Al4V alloy. This contribution will report about the influence of H 2 O 2 concentration on the in vitro corrosion of Ti6Al4V simulating inflammation conditions (low concentration) as well as disinfection procedures (high concentrations). Results on the electrochemical behavior (monitored by impedance spectroscopy), the degraded microstructure (obtained with focused ion beam scanning electron microscopy and transmission electron microscopy) and the impact of the H 2 O 2 -driven degradation on the mechanical properties of the alloy will be presented and discussed. Acknowledgements: The authors gratefully acknowledge the financial support of the French National Research Agency (grant agreement ANR-22-CE93-0007-02) and that of the Swiss National Science Foundation (grant agreement 200021L_213161). References: [1] Prestat et al. , Microstructural aspects of Ti6Al4V degradation in H 2 O 2 -containing phosphate buffered saline , Corros. Sci. 190 (2021) 109640. [2] S. Hedberg et al. , Mechanistic insight on the combined effect of albumin and hydrogen peroxide on surface oxide composition and extent of metal release from Ti6Al4V , J. Biomed. Mater. Res. - Part B Appl. Biomater. 107 (2019) 858. [3] T. Kim et al. , General review of titanium toxicity , Int. J. Impl. Dent. 5 (2019) 10. [4] Prestat et al., Corrosion of titanium under simulated inflammation conditions: clinical context and in vitro investigations , Acta Biomater. 136 (2021) 72. Figure 1: Typical post-mortem SEM top-view micrograph of a Ti6Al4V surface with β phase dissolution (at the grain boundaries) after 30 minutes of exposure at 37 °C in phosphate buffer saline containing 1 M of H 2 O 2 . Figure 1

Degradation

Titanium alloy

10.1149/ma2023-02111070mtgabs

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