Surface observation and measurement techniques to study the fatigue damage micromechanisms in a duplex stainless steel

Bartali, Ahmed El; Aubin, Véronique; Degallaix, Suzanne

doi:10.1016/j.ijfatigue.2008.11.003

Cited by 50 publications

(37 citation statements)

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“…To measure displacements/strains over a period of time, in situ DIC is the only option [24][25][26][27][28][29][30][31]. In situ high resolution deformation measurements (0.1 to 10 μm per image pixel) may be carried out when coupled with optical microscopy [26][27][28][29][30][31]; whilst ultra-high resolution measurements (10-100 nm per image pixel) may be obtained when performed within a SEM [24,25,29,[32][33][34][35][36][37][38][39][40]. Currently, in situ DIC coupled with an optical microscope can provide sufficiently high-resolution in both spatial and temporal deformation measurements, making it a preferred choice for fatigue crack growth studies, as opposed to more sophisticated techniques and specialised apparatus required in SEM-DIC or Synchrotron X-ray setups.…”

Section: Introductionmentioning

confidence: 99%

“…DIC technique has been used in the studies of crack formation and crack growth [25,26,29,41]. Li and Orlecky [25] used fiducial grid for measuring accumulated micro-strains ahead of a fatigue crack tip near aluminium bicrystal interface using SEM.…”

Section: Introductionmentioning

confidence: 99%

“…Li and Orlecky [25] used fiducial grid for measuring accumulated micro-strains ahead of a fatigue crack tip near aluminium bicrystal interface using SEM. El Bartali et al [26] carried out in situ DIC to measure the strain fields over a small area (120μm ×90 μm) on a cylindrical specimen of duplex stainless steel under a fully reversed tension-compression loading. In their study, DIC was performed only at zero applied strain.…”

Section: Introductionmentioning

confidence: 99%

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In Situ Experimental Study of Near-Tip Strain Evolution of Fatigue Cracks

Lupton

Zhu

et al. 2015

Exp Mech

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Near crack tip strain fields in a stationary and a growing fatigue crack have been studied in situ using the Digital Image Correlation (DIC) technique in a compact tension specimen of stainless steel 316 L under tensiontension cyclic loading. The evolution of near-tip strains normal to the crack plane was monitored at selected locations ahead of the crack tip in consecutive cycles during fatigue crack growth experiments. A stationary crack was examined first to provide a baseline reference whilst the evolution of the strain field ahead of a growing crack was monitored in situ at peak loads during fatigue cycling. The results show that strain accumulation with loading cycle occurred at all tracked locations in both cases, and it is particularly evident close to the crack tip. Moreover, a higher strain accumulation rate was found near the growing crack tip than that near the stationary crack tip. The results on near-tip strain evolution were collected for the first time in situ during the fatigue crack growth experiments, which may hopefully inform a physical-based modelling strategy of fatigue crack growth.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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In Situ Experimental Study of Near-Tip Strain Evolution of Fatigue Cracks

Lupton

Zhu

et al. 2015

Exp Mech

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“…Este evento foi observado tanto na amostra do aço no estado como recebido (Figura 5-a) quanto nas amostras do aço após todos os tratamentos térmicos (Figuras 5-a até 5-g) e pode estar relacionado com a orientação cristalográfica de cada fase. Mateo et al [20] e El Bartali et al [21], ao caracterizar aços inoxidáveis duplex laminados, observaram que a fase α tende ao desenvolvimento de textura, fato que pode explicar a dissolução uniforme desta fase, uma vez que a maioria dos grãos estão orientados aproximadamente na mesma direção. Por outro lado, a fase γ pode ter apresentado diferentes graus de dissolução devido a sua ausência de textura, ou seja, maior aleatoriedade de orientação cristalográfica.…”

Section: Resultsunclassified

Utilização Da Microscopia De Força Atômica No Estudo Da Fragilização a 475ºc Em Um Aço Inoxidável Lean Duplex

Reis¹,

Godefroid²,

Andrade³

2018

ABM Proceedings

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ResumoNeste trabalho, a microscopia de força atômica foi empregada para estudo da evolução da fragilização a 475ºC em um aço inoxidável lean duplex. Para tal, amostras deste aço foram submetidas a tratamentos isotérmicos com duração variando entre 1 e 100 horas na temperatura de 475ºC. Ensaios de tenacidade ao impacto e de dureza foram realizados para confirmar a ocorrência da decomposição da fase α. Posteriormente foram realizadas análises no microscópio de força atômica. Os ensaios de tenacidade ao impacto e de dureza indicaram que ocorreu decomposição espinodal da fase α. Medições da diferença da dissolução das fases α e γ, conduzidas no microscópio de força atômica, indicaram que a resistência à dissolução da fase α diminui com o tempo de envelhecimento de forma similar a redução da tenacidade. Os resultados indicam que a microscopia de força atômica é uma ferramenta eficiente para avaliar o grau de evolução da fragilização a 475ºC. Palavras-chave: Microscópio de força atômica; Aços inoxidáveis duplex; Fragilização a 475ºC; Fase α'. USING OF ATOMIC FORCE MICROSCOPY TO STUDY OF THE EMBRITTLEMENT AT 475ºC OF A LEAN DUPLEX STAINLESS STEEL AbstractIn this work, the atomic force microscopy was employed to study the evolution of the embrittlement at 475ºC of a lean duplex stainless steel. For this, samples of this steel were subjected to isothermal treatments with duration between 1 to 100 hours in the temperature of 475ºC. Tests of impact toughness and hardness were carried out to confirm the occurrence of α phase decomposition. Atomic force microscopy analyzes were performed. The impact toughness and hardness tests indicated that α spinodal decomposition has occurred. Measurements of the difference in α and γ phases dissolution, carried out by atomic force microscopy, indicated that the α phase dissolution resistance decreased with time of ageing in the same way as the toughness reduction. The results indicated that the atomic force microscope is an efficient tool to assess the evolution of the embrittlement at 475ºC.

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“…In that context, grid techniques were not considered (Schroeter and McDowell, 2003;Moulart et al, 2009;Badulescu et al, 2009) as they need marks or painting on the surface and a solution by digital image correlation (DIC) was chosen (Besnard et al, 2006;Hild and Roux, 2006;Efstathiou et al, 2010). These two techniques have both been used to provide displacement and strain fields at the grain scale (Moulart et al, 2009;Saai et al, 2010;Efstathiou et al, 2010;Héripré et al, 2007;Schroeter and McDowell, 2003;Raabe et al, 2003;El Bartali et al, 2009). The random surface texture necessary for the image correlation was obtained by a slightly electrochemical etching of the specimen.…”

Section: Experimental Mechanical Field Measurement Techniquementioning

confidence: 99%

Influence of boundary conditions on bi-phased polycrystal microstructure calculation

Evrard

Bartali

Aubin

et al. 2010

International Journal of Solids and Structures

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International audienceIn this paper, polycrystalline bi-phased microstructure calculations were performed using finite element (FE) method and compared to mechanical fields measured experimentally using a digital image correlation (DIC) technique. From scanning electron microscopic (SEM) observations and electron back-scattered diffraction (EBSD) crystal orientation measurements performed on an austenitic-ferritic stainless steel test specimen, a quasi-2D numerical polycrystalline microstructure was constructed. Mechanical behaviors of austenitic (FCC) and ferritic (BCC) grains were modeled by two crystal plasticity laws, based on crystallographic slips and dislocation densities. FE mechanical fields were calculated using two types of boundary conditions: the displacements measured by DIC, and the average of the displacements measured by DIC. A better description of intraphase and intragranular strain heterogeneities is obtained using as boundary conditions the displacements measured instead of the average of the displacements measured

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Surface observation and measurement techniques to study the fatigue damage micromechanisms in a duplex stainless steel

Cited by 50 publications

References 12 publications

In Situ Experimental Study of Near-Tip Strain Evolution of Fatigue Cracks

In Situ Experimental Study of Near-Tip Strain Evolution of Fatigue Cracks

Utilização Da Microscopia De Força Atômica No Estudo Da Fragilização a 475ºc Em Um Aço Inoxidável Lean Duplex

Influence of boundary conditions on bi-phased polycrystal microstructure calculation

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