The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Yanbin Chen - One of the best experts on this subject based on the ideXlab platform.
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morphology and crystallography of lath martensite in weld metal of high strength steel by double sided laser welding
Materials Letters, 2020Co-Authors: Liqun Li, Yanbin ChenAbstract:Abstract The morphology and crystallography of the lath martensite in the weld metal of high strength steel by double-sided hybrid fiber laser-arc welding were investigated. The lath martensite was found to have Kurdjumov-Sachs Orientation relationship. The amount of the lath martensite in the block was affected by the cooling direction of the weld pool. All the four packets were distributed randomly within a columnar grain. The blocks were approximately in square shape. All the 24 variants appeared within the columnar grain and some regions included certain combinations of two particular variants. The lath martensite in the weld metal had preferred Orientation which was lath martensite (1 1 1) ‖ substrate surface.
Joan Kirschner - One of the best experts on this subject based on the ideXlab platform.
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Changes of morphology, structure, and magnetism of Fe on stepped Cu(111)
IEEE Transactions on Magnetics, 1998Co-Authors: M. Klaua, H. Jenniches, Ph. Ohresser, Josef Barthel, Ch. V. Mohan, J Shen, Joan KirschnerAbstract:We have studied the morphology, structure and magnetism of Fe films thermally deposited on stepped Cu(111) by scanning tunnelling microscopy (STM), low energy electron diffraction (LEED) and magneto-optical Kerr effect (MOKE). At room temperature, in the submonolayer range Fe films grow as quasi one-dimensional stripes along the upper step edges due to a strong decoration effect. Between 1.4 and 1.8 monolayer coverage the stripes percolate and become two-dimensional films. Between 2.3 and 2.7 monolayer coverage the films undergo a structural transition from fcc(111) to bcc(110) with Kurdjumov-Sachs Orientation. In the fcc range the films have a low net magnetic moment, and a perpendicular easy magnetization axis. The magnetization switches to an in-plane high-moment phase correlated with the fcc to bcc structural transformation
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STRUCTURAL AND MAGNETIC PHASE TRANSITIONS OF FE ON STEPPED CU(111)
Physical Review B, 1997Co-Authors: J Shen, M. Klaua, H. Jenniches, Josef Barthel, Ch. V. Mohan, Philippe Ohresser, Joan KirschnerAbstract:The magnetism and its correlation with morphology and structure of ultrathin Fe/Cu(111) films have been studied. At room temperature, the films grow in a quasi-one-dimensional form (stripes) in the submonolayer range. Between 1.4 and 1.8 ML the stripes percolate and become two-dimensional films. The remanent magnetization of the percolated films was observed to be significantly more stable with respect to time than that of the stripes. At low thickness (2.3 ML) the films adopt the fcc structure from the substrate and later transform to bcc(110) structure with Kurdjumov-Sachs Orientation. Experimental evidence suggests that the fcc films have a low-spin ferromagnetic or ferrimagnetic phase, and a perpendicular easy magnetization axis. The magnetization switches to an in-plane high-spin phase after the fcc to bcc structural transformation has been accomplished.
Herbert M. Urbassek - One of the best experts on this subject based on the ideXlab platform.
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martensitic transformation of pure iron at a grain boundary atomistic evidence for a two step kurdjumov sachs pitsch pathway
AIP Advances, 2016Co-Authors: Jerome Meiser, Herbert M. UrbassekAbstract:Using classical molecular dynamics simulations and the Meyer-Entel interaction potential, we study the martensitic transformation pathway in a pure iron bi-crystal containing a symmetric tilt grain boundary. Upon cooling the system from the austenitic phase, the transformation starts with the nucleation of the martensitic phase near the grain boundary in a plate-like arrangement. The Kurdjumov-Sachs Orientation relations are fulfilled at the plates. During further cooling, the plates expand and merge. In contrast to the Orientation relation in the plate structure, the complete transformation proceeds via the Pitsch pathway.
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Martensitic transformation of pure iron at a grain boundary: Atomistic evidence for a two-step Kurdjumov-Sachs–Pitsch pathway
AIP Advances, 2016Co-Authors: Jerome Meiser, Herbert M. UrbassekAbstract:Using classical molecular dynamics simulations and the Meyer-Entel interaction potential, we study the martensitic transformation pathway in a pure iron bi-crystal containing a symmetric tilt grain boundary. Upon cooling the system from the austenitic phase, the transformation starts with the nucleation of the martensitic phase near the grain boundary in a plate-like arrangement. The Kurdjumov-Sachs Orientation relations are fulfilled at the plates. During further cooling, the plates expand and merge. In contrast to the Orientation relation in the plate structure, the complete transformation proceeds via the Pitsch pathway.
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Martensitic and austenitic phase transformations in Fe-C nanowires
Modelling and Simulation in Materials Science and Engineering, 2014Co-Authors: Binjun Wang, Emilia Sak-saracino, Luis Sandoval, Herbert M. UrbassekAbstract:Using molecular-dynamics simulation, we study the austenitic and martensitic phase transformation in Fe–C nanowires with C contents up to 1.2 at%. The transformation temperatures decrease with C content. The martensite temperature decreases with wire diameter towards the bulk value. During the transformation, the bcc and fcc phases obey the Kurdjumov–Sachs Orientation relationship. For ultrathin wires (diameter D ≤ 2.8 nm), we observe wire buckling as well as shape-memory effects. Under axial tensile stress the martensite transformation is partially suppressed, leading to strong plastic deformation. Under the highest loads, the austenite only partially back-transforms while the crystalline phases in the wire re-orient giving the multi-phase mixture a high tensile strength.
Liqun Li - One of the best experts on this subject based on the ideXlab platform.
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morphology and crystallography of lath martensite in weld metal of high strength steel by double sided laser welding
Materials Letters, 2020Co-Authors: Liqun Li, Yanbin ChenAbstract:Abstract The morphology and crystallography of the lath martensite in the weld metal of high strength steel by double-sided hybrid fiber laser-arc welding were investigated. The lath martensite was found to have Kurdjumov-Sachs Orientation relationship. The amount of the lath martensite in the block was affected by the cooling direction of the weld pool. All the four packets were distributed randomly within a columnar grain. The blocks were approximately in square shape. All the 24 variants appeared within the columnar grain and some regions included certain combinations of two particular variants. The lath martensite in the weld metal had preferred Orientation which was lath martensite (1 1 1) ‖ substrate surface.
J Shen - One of the best experts on this subject based on the ideXlab platform.
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Changes of morphology, structure, and magnetism of Fe on stepped Cu(111)
IEEE Transactions on Magnetics, 1998Co-Authors: M. Klaua, H. Jenniches, Ph. Ohresser, Josef Barthel, Ch. V. Mohan, J Shen, Joan KirschnerAbstract:We have studied the morphology, structure and magnetism of Fe films thermally deposited on stepped Cu(111) by scanning tunnelling microscopy (STM), low energy electron diffraction (LEED) and magneto-optical Kerr effect (MOKE). At room temperature, in the submonolayer range Fe films grow as quasi one-dimensional stripes along the upper step edges due to a strong decoration effect. Between 1.4 and 1.8 monolayer coverage the stripes percolate and become two-dimensional films. Between 2.3 and 2.7 monolayer coverage the films undergo a structural transition from fcc(111) to bcc(110) with Kurdjumov-Sachs Orientation. In the fcc range the films have a low net magnetic moment, and a perpendicular easy magnetization axis. The magnetization switches to an in-plane high-moment phase correlated with the fcc to bcc structural transformation
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STRUCTURAL AND MAGNETIC PHASE TRANSITIONS OF FE ON STEPPED CU(111)
Physical Review B, 1997Co-Authors: J Shen, M. Klaua, H. Jenniches, Josef Barthel, Ch. V. Mohan, Philippe Ohresser, Joan KirschnerAbstract:The magnetism and its correlation with morphology and structure of ultrathin Fe/Cu(111) films have been studied. At room temperature, the films grow in a quasi-one-dimensional form (stripes) in the submonolayer range. Between 1.4 and 1.8 ML the stripes percolate and become two-dimensional films. The remanent magnetization of the percolated films was observed to be significantly more stable with respect to time than that of the stripes. At low thickness (2.3 ML) the films adopt the fcc structure from the substrate and later transform to bcc(110) structure with Kurdjumov-Sachs Orientation. Experimental evidence suggests that the fcc films have a low-spin ferromagnetic or ferrimagnetic phase, and a perpendicular easy magnetization axis. The magnetization switches to an in-plane high-spin phase after the fcc to bcc structural transformation has been accomplished.
