The Experts below are selected from a list of 144 Experts worldwide ranked by ideXlab platform
Carmen Garciamateo - One of the best experts on this subject based on the ideXlab platform.
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new experimental evidence of the diffusionless transformation nature of bainite
Journal of Alloys and Compounds, 2013Co-Authors: F G Caballero, Carmen Garciamateo, M K Miller, Juan CornideAbstract:Abstract Since the discovery of bainite, research over many decades has revealed a substantial amount of information about the mechanism of the bainite transformation in steels. Elements of the theory are now routinely being used in many parts of the world in the design of novel alloys and in the interpretation of a variety of experimental data. However, current experimental and theoretical understanding is limiting technological progress. The purpose of this atom probe tomography study was to track atom distributions during the bainite reaction in a nanocrystalline steel. The results are providing new experimental evidence on subjects critically relevant to the understanding of the atomic mechanisms controlling bainitic ferrite formation, such as the incomplete transformation phenomenon, the carbon supersaturation of ferrite, and the plastic accommodation of the Surrounding Austenite.
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complementary use of transmission electron microscopy and atom probe tomography for the examination of plastic accommodation in nanocrystalline bainitic steels
Acta Materialia, 2011Co-Authors: F G Caballero, Juan Cornide, M K Miller, Jerren Yang, Carmen GarciamateoAbstract:Abstract A displacive transformation involves the motion of a glissile interface. As in work hardening, its motion can be halted by defects such as dislocations, stacking faults or twins in the Austenite. The defects are created when the shape deformation accompanying bainite growth is accommodated by plastic relaxation of the Surrounding Austenite. The growing plate stops when it collides with the Austenite grain boundary. Because transformation from strong Austenite leads to fine plates, alloys can be designed such that the bainite transformation is suppressed to low temperatures (125–350 °C), leading to a nanoscale bainitic microstructure. Complementary high-resolution transmission electron microscopy and atom probe tomography have provided new experimental evidence on the accommodation of transformation strain, a subject critically relevant to understanding the atomic mechanisms controlling bainitic ferrite growth.
F G Caballero - One of the best experts on this subject based on the ideXlab platform.
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new experimental evidence of the diffusionless transformation nature of bainite
Journal of Alloys and Compounds, 2013Co-Authors: F G Caballero, Carmen Garciamateo, M K Miller, Juan CornideAbstract:Abstract Since the discovery of bainite, research over many decades has revealed a substantial amount of information about the mechanism of the bainite transformation in steels. Elements of the theory are now routinely being used in many parts of the world in the design of novel alloys and in the interpretation of a variety of experimental data. However, current experimental and theoretical understanding is limiting technological progress. The purpose of this atom probe tomography study was to track atom distributions during the bainite reaction in a nanocrystalline steel. The results are providing new experimental evidence on subjects critically relevant to the understanding of the atomic mechanisms controlling bainitic ferrite formation, such as the incomplete transformation phenomenon, the carbon supersaturation of ferrite, and the plastic accommodation of the Surrounding Austenite.
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complementary use of transmission electron microscopy and atom probe tomography for the examination of plastic accommodation in nanocrystalline bainitic steels
Acta Materialia, 2011Co-Authors: F G Caballero, Juan Cornide, M K Miller, Jerren Yang, Carmen GarciamateoAbstract:Abstract A displacive transformation involves the motion of a glissile interface. As in work hardening, its motion can be halted by defects such as dislocations, stacking faults or twins in the Austenite. The defects are created when the shape deformation accompanying bainite growth is accommodated by plastic relaxation of the Surrounding Austenite. The growing plate stops when it collides with the Austenite grain boundary. Because transformation from strong Austenite leads to fine plates, alloys can be designed such that the bainite transformation is suppressed to low temperatures (125–350 °C), leading to a nanoscale bainitic microstructure. Complementary high-resolution transmission electron microscopy and atom probe tomography have provided new experimental evidence on the accommodation of transformation strain, a subject critically relevant to understanding the atomic mechanisms controlling bainitic ferrite growth.
Juan Cornide - One of the best experts on this subject based on the ideXlab platform.
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new experimental evidence of the diffusionless transformation nature of bainite
Journal of Alloys and Compounds, 2013Co-Authors: F G Caballero, Carmen Garciamateo, M K Miller, Juan CornideAbstract:Abstract Since the discovery of bainite, research over many decades has revealed a substantial amount of information about the mechanism of the bainite transformation in steels. Elements of the theory are now routinely being used in many parts of the world in the design of novel alloys and in the interpretation of a variety of experimental data. However, current experimental and theoretical understanding is limiting technological progress. The purpose of this atom probe tomography study was to track atom distributions during the bainite reaction in a nanocrystalline steel. The results are providing new experimental evidence on subjects critically relevant to the understanding of the atomic mechanisms controlling bainitic ferrite formation, such as the incomplete transformation phenomenon, the carbon supersaturation of ferrite, and the plastic accommodation of the Surrounding Austenite.
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complementary use of transmission electron microscopy and atom probe tomography for the examination of plastic accommodation in nanocrystalline bainitic steels
Acta Materialia, 2011Co-Authors: F G Caballero, Juan Cornide, M K Miller, Jerren Yang, Carmen GarciamateoAbstract:Abstract A displacive transformation involves the motion of a glissile interface. As in work hardening, its motion can be halted by defects such as dislocations, stacking faults or twins in the Austenite. The defects are created when the shape deformation accompanying bainite growth is accommodated by plastic relaxation of the Surrounding Austenite. The growing plate stops when it collides with the Austenite grain boundary. Because transformation from strong Austenite leads to fine plates, alloys can be designed such that the bainite transformation is suppressed to low temperatures (125–350 °C), leading to a nanoscale bainitic microstructure. Complementary high-resolution transmission electron microscopy and atom probe tomography have provided new experimental evidence on the accommodation of transformation strain, a subject critically relevant to understanding the atomic mechanisms controlling bainitic ferrite growth.
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Distribution of Dislocations in Nanostructured Bainite
Solid State Phenomena, 2011Co-Authors: Juan Cornide, Michael K Miller, Goro Miyamoto, Francisca García Caballero, Tadashi Furuhara, Carlos Garcia-mateoAbstract:The dislocation density in ferrite and Austenite of a bainitic microstructure obtained by transformation at very low temperature (300 °C) has been determined using transmission electron microscopy. Observations revealed that bainitic ferrite plates consist of two distinctive regions with different substructures. A central region in the ferrite plate is observed with dislocations that may result from lattice-invariant deformation at the earlier stage of bainite growth. As plastic deformation occurs in the Surrounding Austenite to accommodate the transformation strain as growth progresses, the Ferrite/Austenite interface has also a very distinctive dislocation profile. In addition, atom-probe tomography suggested that dislocation tangles observed in the vicinity of the ferrite/Austenite interface might trap higher amount of carbon than single dislocations inside the bainitic ferrite plate.
Saeed Heshmati-manesh - One of the best experts on this subject based on the ideXlab platform.
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Micro and macro-mechanical behavior of a transformation-induced plasticity steel developed by thermomechanical processing followed by quenching and partitioning
Materials Science and Engineering: A, 2016Co-Authors: M. Karam-abian, Abbas Zarei-hanzaki, Hamid Reza Abedi, Saeed Heshmati-maneshAbstract:Abstract A low-alloyed transformation induced plasticity steel was subjected to thermomechanical processing (TMP) followed by quenching and partitioning treatment to achieve a desired combination of the strength and ductility. The developed microstructures were precisely analyzed, and the mechanical responses of individual micro-constituents were studied by nanoindentation using a reliable scanning probe microscopy. The results indicate that the characteristics of the constituent phases (i.e., the lath martensite, blocky fresh martensite and the retained Austenite) were dictated by the prior TMP. The occurrence of dynamic recrystallization and the formation of equiaxed-shape fine Austenite grains during TMP would provide fast diffusion track for carbon to diffuse through the untransformed Austenite. The carbon partitioning from martensite to the Surrounding Austenite ensures the Austenite stabilization and was identified as the major factor for martensite softening at micro-scale level. The room temperature mechanical properties were studied via shear punch and tensile testing methods. The obtained superior mechanical properties, the ultimate tensile stress of ~1400 MPa and shear elongation to fracture of ~19% were justified considering the proper work hardening behavior of the material.
Jun-seog Yang - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of thermal ageing activation energy of δ-ferrite in an austenitic stainless steel weld using nanopillar compression test
Scripta Materialia, 2020Co-Authors: Byeong Seo Kong, Jiho Shin, Gokul Obulan Subramanian, Junjie Chen, Changheui Jang, Dongchan Jang, Ho Jung Lee, Jun-seog YangAbstract:Abstract Nanopillar compression tests were applied on δ-ferrites in austenitic stainless steel welds to measure the thermal ageing activation energy caused by spinodal decomposition. Welds of an austenitic stainless steel were thermally aged at 343, 375, and 400 oC for up to 20,000 h. To avoid the interference of Surrounding Austenite matrix on embrittlement measurement, Austenite matrix was selectively dissolved before the nanopillar fabrication. Using the yield stress changes measured by nanopillar compression tests, the thermal ageing activation energy of δ-ferrite was estimated as 154 KJ/mol, which was compared with literature results and the reasons of discrepancy were discussed.