Didier Chicot

Didier Chicot
University Lille Nord de France · LGCgE ULR4515

HDR in Materials Science

About

199
Publications
50,365
Reads
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3,318
Citations
Additional affiliations
September 1993 - present
University of Lille Nord de France
Position
  • Professor (Full)
Description
  • Materials science in teaching and Mechanical Characterization by Instrumented Indentation in research

Publications

Publications (199)
Article
Three-dimensional (3D) printable concrete requires cementitious material that must have suitable but self-contradictory properties to be printable such as fluidity to facilitate pumping along with stiffness and strength to ensure buildability, both having a great influence on the cohesion of the interfacial zone. A pool of characterization tests wa...
Article
Full-text available
A microhardness tester equipped with a Vickers indenter allows the determination of mechanical properties of a large variety of materials by analyzing load–displacement curves. In present work, a new model to compute the coefficient of proportionality K (named K-factor) between P and h relating to the pile-up have been developed. It was proved that...
Article
Instrumented indentation testing is widely used to determine the mechanical properties of materials. In particular, this technique makes it possible to study brittle materials for which cracks can be generated around the impression during the indentation test. Cracking can result in the formation of pop-ins on the curve load-segment which can be us...
Article
A study was conducted to investigate the effects of surface microhardness on different phases of fatigue damage. This helps to estimate the evolution of the material resistance from microplastic distortions and gives pertinent data about cumulated fatigue damage. The objective of this work is to propose a damage criterion, associated with microstru...
Article
Depending on the thermal spraying conditions, coatings obtained can present different defects, like pores, cracks and/or unmelted particles, and different surface roughnesses, that can affect the determination of the hardness and elastic modulus. The present work investigates the mechanical properties, determined by means of Knoop and Vickers inden...
Article
Full-text available
The resistance to separation of the concrete from its reinforcing steel with which it is in contact is called adhesion .This adhesion constitutes an important property for the use of reinforced concrete. That is why many techniques were developed with the aim of determining this property. Adhesion can be easily found out by standard pullout test ma...
Article
The basis of the virtual machine concept, which is commonly used in coordinate measuring machines, was implemented to determine more realistic uncertainties on the estimation of the elastic modulus obtained from nanoindentation tests. The methodology is based on a mathematical model applied to simulate the testing process and to evaluate the uncert...
Article
To ensure reinforced concrete bars applications in more severe loading conditions, the contact between the steel bar and concrete must be strongly adhesive. This adhesion constitutes an important property for the use of reinforced concrete. That is why many techniques were developed with the aim of determining this property. Adhesion can be easily...
Article
In this research indentation instrument testing is used as a new method for local characterization to study different zones of friction stir welded AA6061 alloy. For this purpose nanoindentation and microhardness are applied for samples in as-weld and post weld heat treatment conditions. Nugget zone, thermomechanically affected zone, and heat affec...
Article
Cracking resistance or fracture toughness of brittle materials, such as optical glasses, can be determined by Vickers indentation, which allows generating cracks along the diagonals of the indent whose length depends of the loading rate. Subsequently, a relationship between the crack length and the corresponding indentation load is applied to calcu...
Article
Full-text available
This work is focused on the mechanical characterization by multiscale indentation (nano and macro) of a brake pad material, with multiple phases and complex microstructure for applications in the railway industry. Grid nanoindentation tests allowed to identify the mechanical properties of the components in the formulation. The significant differenc...
Article
Steel slags are industrial by-products of an integrated steel plant, characterized by their high calcium, siliceous and ferrous content. They prove useful in many fields, such as civil engineering and in the process of steelmaking for the iron-rich phases. For a better valuation, it is important to optimize the separation of its phases. To separate...
Article
In this study the behavior of brazing joints with nickel-silicon-based amorphous alloys ribbons was analyzed in terms of mechanical strength and corrosion resistance. Two Ni78Si8B15 and Ni68Fe3Cr7Si8B14 metallic glasses ribbons designed and fabricated in our laboratory have been studied as brazing foils. The base material of the joint is the 316L a...
Article
Full-text available
Resumen Las propiedades de los recubrimientos a base de circonia estabilizada con ytria (YSZ) confieren a estos un excelente desempeño en una amplia gama de aplicaciones que van desde el uso odontológico hasta barreras térmicas, incluyendo también su empleo como electrolitos sólidos en celdas de combustible. En el presente trabajo, se depositaron r...
Article
Full-text available
Influence of TiB2 addition in nickel-based coatings is studied from different point of views, microstructural (phases identification and porosity rate), mechanical (hardness and elastic modulus by instrumented indentation) and mechanical behavior (wear resistance by pin-on-disk system). In the two coatings containing 2.5 and 10% of TiB2, we note th...
Article
The present work reports on the influence of nickel molar loading and impregnation solutions, nitrate salts and copper and nickel ammonium complexes, on the synthesis of Ni-Cu catalyst supported on alumina for obtaining carbon nanofibers by catalytic chemical vapor deposition of methane. These catalysts were characterized by N2 adsorption-desorptio...
Article
Abstract Scanning electron microscopy, X-ray diffraction and Fourier transformed infrared spectroscopy have been used to characterize the microstructure and instrumented microindentation for the determination of the mechanical properties of Charonia Lampas Lampas shell. Both elastic modulus and hardness are found to be dependent on the texture of t...
Conference Paper
The hardness of a material shows its ability to resist to microplastic deformation caused by indentation or penetration and is closely related to the plastic slip capacity of the material. Therefore, it could be significant to study the resistance to microplastic deformations based on microhardness changes on the surface, and the associated accumul...
Article
Full-text available
The present study has been conducted in order to obtain titanium carbide layer using a conversion treatment consisting of two main steps. In the first step a thin pure titanium layer was deposited on 120C4 carbon steel by PVD. In the second step, the carbon atoms from the substrate diffuse to the titanium coating due to a vacuum annealing treatment...
Article
The interfacial indentation test is experimented for the first time in order to characterize the adhesion between the concrete and its steel reinforcement. This technique, developed to estimate the adhesion of thick coatings (thermal barrier, plasma torch deposits, etc.), is used here to create and propagate a crack along the concrete/reinforcement...
Article
The assessment of mechanical properties of materials by instrumented indentation tests have been widely performed in last years. The objective of this work was to develop a methodology to analyze the mechanical behavior of materials from the data obtained by a continuous multicycle indentation test at the microscale of loads to limit the problems a...
Conference Paper
Fatigue is a major cause of failures concerning metal structures, being capable of causing catastrophic damage to the environment and considerable financial loss. Steel pipelines used in oil and gas industry for hydrocarbon transportation, for instance, are submitted to the action of cyclic loads, being susceptible to undergo fatigue failures. The...
Article
Full-text available
This study investigated the effectiveness of titania (TiO2) as a reinforcing phase in the hydroxyapatite (HAP) coating and silica (SiO2) single layer as a bond coat between the TiO2-reinforced hydroxyapatite (TiO2/HAP) top layer and 316L stainless steel (316L SS) substrate on the corrosion resistance and mechanical properties of the underlying 316L...
Article
Full-text available
The unloading part of a load–displacement curve from instrumented indentation tests is usually approximated by a power law (Oliver and Pharr model), where the load is the dependent variable. This approach generally fits well the data. Nevertheless, the convergence is occasionally quite questionable. In this regard, we propose a different approach f...
Article
Study of creep and relaxation behaviours of materials submitted to severe conditions in terms of temperature, stress and strain is necessary but sometimes very expensive with classical tests. Indeed, these tests, mainly the creep one, are very time-consuming since it can last more than one year. In order to drastically reduce this duration, we sugg...
Article
Ceramics generally have a lower Knoop than Vickers hardness. This difference is due to the elastic recovery occurring around a Knoop indentation and the difference in representative area considered to calculate the hardness value.Conventional hardness tests with Knoop and Vickers indenters were performed in order to show how Knoop hardness test can...
Article
Full-text available
In this work, nano, micro, and macro-indentation tests under standard or multicycle loading conditions were performed for studying the mechanical behavior of a crown borosilicate glass sample with the objective to study the scale effect in indentation and the influence of cracks formation on the assessment of mechanical properties. When no cracks w...
Article
L’essai d’indentation instrumentée est une technique très utilisée car elle permet d’estimer les propriétés mécaniques des matériaux comme la dureté et le module de Young. Cette étude sur l’indentation multi-échelles (de 5 mN à 2 kN) a été réalisée sur des matériaux métalliques massifs (acier, acier inoxydable et aluminium) avec trois instruments :...
Article
Titania-Hydroxyapatite (TiO2/HAP) reinforced coatings are proposed to enhance the bioactivity and corrosion resistance of 316L stainless steel (316L SS). Herein, spin- and dip-coating sol-gel processes were investigated to construct two kinds of coatings: TiO2/HAP composite and TiO2/HAP bilayer. Physicochemical characterization highlighted the bioa...
Article
The mechanical properties of solution precursor plasma sprayed hydroxyapatite (SPPS-HA) coatings were investigated by instrumented indentation test in relation to their microstructural characteristics. The morphology of the coatings using solution that is more concentrated shows cauliflower-like surface with fine particles and agglomerated fragment...
Conference Paper
Full-text available
The paper describes the investigations of mechanical properties of various zirconia coatings having different microstructure, phase content and chemical composition. The coatings were deposited using Suspension Plasma Spraying technology. The suspensions were formulated using three different powders: (i) ZrO2 + 8 wt.% Y2O3, (ii) ZrO2 + 14 wt.% of Y...
Article
Elastic modulus of a large variety of materials: low-carbon steel, rolled and rapid prototyping stainless steels, aluminum, brass, beta tricalcium phosphate (β-TCP) bioceramic and the TiB2-60% B4C composite ceramic were determined by Vickers instrumented indentation tests. A relationship the ratio of elastic recovery energy to total work-of-indenta...
Article
During the last past decades, galvanised steels have been extensively developed to improve corrosion resistance of steels due to their excellent chemical properties particularly in severe atmospheric conditions. The objective of this work is to predict the hardness-load variation in relation to the bath immersion time using both a m ultilayer coati...
Article
Full-text available
Zinc and some of its alloys have a number of characteristics that make it well suited for use as a protective coating against the corrosion of steel substrates under severe atmospheric conditions. The metal of zinc, which represents the main galvanization element offer then a cathodic protection to the ferrous materials. Because of these excellent...
Article
Full-text available
Elastic modulus of a large variety of materials: low-carbon steel, rolled and rapid prototyping stainless steels, aluminum, brass, beta tricalcium phosphate (β-TCP) bioceramic and the TiB2-60% B4C composite ceramic were determined by Vickers instrumented indentation tests. A relationship the ratio of elastic recovery energy to total work-of-indenta...
Article
The mechanical property determination of thin films by nanoindentation can be affected by the substrate depending on the indentation testing conditions and the film thickness. In this condition and especially for very thin films, application of models is required for separating the substrate influence of the indentation measurement. In this paper,...
Article
Hardness Modeling Aluminum nitride Thin films The mechanical property determination of thin films by nanoindentation can be affected by the substrate depending on the indentation testing conditions and the film thickness. In this condition and especially for very thin films, application of models is required for separating the substrate influence o...
Article
Full-text available
The present paper reports on the influence of the addition of TiO2 and SiO2 oxides as sub-layer, on the morphological and mechanical properties of the hydroxyapatite (HAP) bioceramic coatings deposited on 316L stainless steel by sol–gel method in order to improve the properties of hydroxyapatite and expand its clinical application. The stability of...
Article
Full-text available
The present study has been conducted in order to investigate the coupled effects of substrate microstructure and the sulphuric acid anodizing process, on the fatigue life of a 2017A aluminum alloy, by means of plane bending fatigue tests (R = −1). The effect of two different tempers, namely artificially aging (T6) and recovery annealing, prior to a...
Article
Full-text available
In the context of a universal search for alternatives to chromate-based coatings, which are toxic for both human beings and the environment, a multilayer coating for Al protection purposes is developed and investigated in the current work. The first layer is selected to be a hexamethyldisiloxane-based plasma polymer film (PPF), deposited by Plasma...
Article
Au cours d’un essai d’indentation, la matière se déforme sous l’indenteur se traduisant physiquement par une déflection des faces de l’empreinte ou par la formation d’un bourrelet à la surface du matériau selon son comportement mécanique. La façon dont la matière va s’écouler influence la détermination des propriétés mécaniques, en particulier via...
Article
Les propriétés mécaniques des films minces sont généralement déterminées par nanoindentation pour éviter l’influence du substrat. En effet, nous savons que le substrat influence cette mesure dès lors que l’indenteur pénètre à plus de 10 % de l’épaisseur du film pour la dureté, ce chiffre pouvant être ramené à 1 % pour le module d’élasticité. Pour d...
Article
Full-text available
Nanostructured yttria-stabilized zirconia coatings for applications in high-temperature environments can be deposited by suspension plasma spraying (SPS) techniques. The present research has been conducted in order to study the sliding wear response of a SPS ZrO2–8% mol. Y2O3 coating (75 μm in thickness) deposited onto a Haynes 230 substrate, using...
Article
The development of sound constitutive descriptions able to predict accurately the changes in flow stress during plastic deformation, under changing temperature and strain rate conditions is of utmost importance for the correct prediction of the mechanical response of metals and alloys, which undergo deformation under hot-working conditions. Therefo...
Article
The paper examines the cracks initiation, propagation and coalescence until failure in a crystalline rock under stress states involving rock volumes varying in size, from nano (Berkovich indentation in Continuous Stiffness Measurement mode) to micro (Vickers indentation, scratching) and macro (Rockwell indentation, Rock Impact Hardness Number) scal...
Article
Full-text available
Instrumented indentation tests have been conducted on the surface and cross-section of the two WC based coatings obtained by means of high velocity oxygen fuel thermal spray techniques in order to investigate their mechanical properties. The yield strength of the coatings has been determined by means of the Zeng and Chiu model. In addition, the abs...
Article
In nanoindentation, especially at very low indenter displacements, the indenter/material contact area must be defined in the best possible way in order to accurately determine the mechanical properties of the material. One of the best methodologies for the computation of the contact area has been proposed by Oliver and Pharr [W.C. Oliver, G.M. Phar...