Dislocation substructure as a function of strain in a dual-phase steel

Korzekwa, Deniece R; Matlock, David K.; Krauß, G.

doi:10.1007/bf02644716

Cited by 143 publications

(52 citation statements)

References 14 publications

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“…De momento, se ha utilizado microscopia electrónica de transmisión para observar fenómenos locales en las proximidades de la intercara con la martensita [31][32][33] . En el presente trabajo se ha pretendido obtener información a una escala más grande y, para ello, se ha llevado a cabo la caracterización mediante EBSD/OIM de los diferentes materiales estudiados.…”

Section: R Re Es Su Ul Lt Ta Ad Do Os S Y Y D Di Is Sc Cu Us Si unclassified

Aplication of nanoindentation and EBSD techniques in complex microstructures steels.

Altuna¹,

Gutiérrez²

2008

Rev. metal.

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Los aceros duales están constituidos básicamente por una matriz ferrítica en la que se encuentran dispersas islas de martensita [1 y 2] . La microestructura dual puede obtenerse directamente tras la laminación en caliente [3 y 4] o calentando un acero ferrito-perlítico hasta una temperatura perteneciente al rango intercríti-co α/γ, seguido de enfriamiento rápido que permita transformar a martensita las regiones de austenita [2 y 5] . La presencia de esta fase dura hace que estos aceros presenten una alta resistencia y la ferrita, al ser una fase blanda, es la que le aporta al acero unas propiedades buenas de ductilidad. Los duales también se caracterizan por presentar una gran conformabilidad, debido a que presentan un valor pequeño de σ y /UTS con un alto coeficiente de endurecimiento.Los ensayos de tracción dan información sobre el comportamiento global del material, pero si se pretende profundizar en el análisis del comportamiento de estos aceros se requieren técnicas más finas de ensayo y observación. En principio, la técnica de nanoindentación parece una técnica adecuada para evaluar las propiedades mecánicas de recubrimientos [6] o de microestructuras mixtas dado que permite la realización de indentaciones de unos cuantos nanómetros de profundidad. El método desarrollado por Oliver y Pharr [7] permite determinar la dureza y el módulo A Ap pl li ic ca ac ci ió ón n d de e t té éc cn ni ic ca as s d de e n na an no oi in nd de en nt ta ac ci ió ón n y y E EB BS SD D e en n a ac ce er ro os s c co on n m mi ic cr ro oe es st tr ru uc ct tu ur ra as s c co om mp pl le ej ja as s (A. Altuna * e I. Gutiérrez * R Re es su um me en n En el presente trabajo, se ha estudiado el comportamiento mecánico de aceros con microestructuras ferrito-perlíticas y ferrito-martensíticas y la relación de estas con la microestructura. Se han obtenido las diferentes microestructuras mediante tratamientos térmicos. Mediante metalografía cuantitativa se ha determinado la fracción volumétrica de cada fase y el tamaño de grano de la ferrita. Para la caracterización mecánica, se han realizado ensayos de tracción. Con el fin de analizar el comportamiento mecánico de cada fase, se ha utilizado la técnica de nanoindentación. Se ha observado que la ferrita tiene mayor dureza si se encuentra en una microestructura ferrito-martensítica que si está en una ferrito-perlítica. Por ello, se ha estudiado el efecto que tiene la presencia de martensita en las características de la ferrita. En este estudio se han aplicado técnicas de EBSD/OIM, con las que se han analizado las desorientaciones presentes en el interior de los granos de ferrita. P Pa al la ab br ra as s c cl la av ve eEndurecimiento ferrita. Martensita. Nanoindentación. EBSD.A Ap pl li ic ca at ti io on n o of f n na an no oi in nd de en nt ta at ti io on n a an nd d E EB BS SD D t te ec ch hn ni iq qu ue es s i in n c co om mp pl le ex x m mi ic cr ro os st tr ru uc c--t tu ur re es s s st te ee el ls s A Ab bs st tr ra ac ct tIn the present work, the mechanical behaviour of ferriti...

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Section: R Re Es Su Ul Lt Ta Ad Do Os S Y Y D Di Is Sc Cu Us Si unclassified

Aplication of nanoindentation and EBSD techniques in complex microstructures steels.

Altuna¹,

Gutiérrez²

2008

Rev. metal.

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“…The strain-hardening rate of the DP steel is higher at low strains (stage I) than in the TRIP steel, which is believed to be associated with the interactions of the quenched-in dislocations and residual stresses with the applied stress. [14] In stages I and III for the DP steel, the strainhardening rate decreases more rapidly for strains of <0.003 and >0.02 than in stage II for strains between 0.003 and 0.02 (Figure 3(b)). The strain-hardening rate curve of the TRIP steel showed only two stages, and the transition from stage I to stage II happened at a higher strain of 0.005 (Figure 3(b)).…”

Section: A Microstructure and Mechanical Properties Of Dp And Trip Smentioning

confidence: 99%

“…The differences in strainhardening behavior of the TRIP and DP steels appeared to be due to the different dislocation substructures formed in ferrite during deformation and the TRIP effect occurred in the TRIP steel as a result of applied stress. [14] B. Comparison of the Microstructures of the DP Steel After Tensile Deformation and Stamping…”

Section: A Microstructure and Mechanical Properties Of Dp And Trip Smentioning

confidence: 99%

“…The stages of strain-hardening rate behavior for both steels were identified according to the changes in the slope of the curve, i.e., by the rate at which the strain hardening decreases with increasing strain. [14] The character and number of regions or stages on the curves depend on the microstructural parameters such as grain size, volume fraction of the retained austenite or martensite. The strain-hardening rate of the DP steel is higher at low strains (stage I) than in the TRIP steel, which is believed to be associated with the interactions of the quenched-in dislocations and residual stresses with the applied stress.…”

Section: A Microstructure and Mechanical Properties Of Dp And Trip Smentioning

confidence: 99%

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The Formation of Complex Microstructures After Different Deformation Modes in Advanced High-Strength Steels

Timokhina

Pereloma

Hodgson

2014

Metall Mater Trans A

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The microstructure of transformation induced plasticity (TRIP) and dual phase (DP) multiphase steels after stamping of an industrial component at different strain levels was investigated using transmission electron microscopy. The TRIP steel microstructure showed a more complex dislocation substructure of ferrite at different strain levels than DP steel. The deformation microstructure of the stamped parts was compared to the deformation microstructure in these complex steels for different "equivalent" tensile strains. It was found that the microstructures are similar only at high levels of strain (>10 pct) for both steels. The microstructure of transformation induced plasticity (TRIP) and dual phase (DP) multiphase steels after stamping of an industrial component at different strain levels was investigated using transmission electron microscopy. The TRIP steel microstructure showed a more complex dislocation substructure of ferrite at different strain levels than DP steel. The deformation microstructure of the stamped parts was compared to the deformation microstructure in these complex steels for different ''equivalent'' tensile strains. It was found that the microstructures are similar only at high levels of strain (>10 pct) for both steels.

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“…[9,10]. Transmission electronic microscopy (TEM) was used to qualitatively understand local dislocation accumulation in the vicinity of ferrite-martensite interfaces in dual-phase steels (DP steels) [11]. However, TEM studies have the shortcoming that only a small area can be observed.…”

Section: Introductionmentioning

confidence: 99%

Quantification and localization of the liquid zone of partially remelted M2 tool steel using X-ray microtomography and scanning electron microscopy

Pesci

Becker

et al. 2012

Acta Materialia

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. In situ tensile tests were performed at room temperature on a ferrite-cementite steel specifically designed for this study. The evolution of the average stress in ferrite during loading was analyzed by Xray diffraction. Lattice strain measurements were performed with synchrotron ring diffraction in both ferrite and cementite. These in situ tests were complemented by macroscopic tensile and reversible tensile-compression tests to study the Bauschinger effect. In order to reproduce stresses in ferrite and cementite particles, a recently developed micromechanical Internal Length Mean Field (ILMF) model based on a generalized self-consistent scheme is applied. In this designed ferrite-cementite steel, the third ''phase'' of the model represents finite intermediate ''layers'' in ferrite due to large geometrically necessary dislocation (GND) densities around cementite particles. The assumed constant thickness of the layers is calibrated thanks to the obtained experimental data. The ILMF model is validated by realistic estimates of the Bauschinger stress and the large difference between mean stresses in ferrite and in cementite phases. This difference cannot be reproduced by classic two-phase homogenization schemes without intermediate GND layers.

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Dislocation substructure as a function of strain in a dual-phase steel

Cited by 143 publications

References 14 publications

Aplication of nanoindentation and EBSD techniques in complex microstructures steels.

Aplication of nanoindentation and EBSD techniques in complex microstructures steels.

The Formation of Complex Microstructures After Different Deformation Modes in Advanced High-Strength Steels

Quantification and localization of the liquid zone of partially remelted M2 tool steel using X-ray microtomography and scanning electron microscopy

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