TY - JOUR A1 - Farooq, M. U. A1 - Klement, U. A1 - Nolze, Gert T1 - Microstructural characterisation of a Co-Cr-Mo laser clad applied on railway wheels N2 - A Co-Cr-Mo laser cladding applied on railway wheels is characterised by a combination of EBSD and EDX. A complete pass of the cladding is investigated to achieve a better understanding of the microstructure evolution during laser cladding. A microstructure with columnar grains extending over the whole thickness of the cladding is observed. The grains have a <001>-fibre texture with the fibre axis parallel to the normal of the substrate surface, and a substructure consisting of cells/dendrites. During the cladding process, two different kinds of precipitates form in the cell walls, which can be identified as M6C and a non-equilibrium phase. Furthermore, stacking faults are observed to occur in the cladding grains and are discussed with respect to the laser cladding process. KW - Laser cladding KW - Co-Cr-Mo KW - EBSD KW - Carbides PY - 2006 DO - https://doi.org/10.3139/146.101312 SN - 1862-5282 VL - 97 IS - 6 SP - 838 EP - 844 PB - Hanser CY - München AN - OPUS4-13973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Farooq, M. U. A1 - Klement, U. A1 - Nolze, Gert T1 - EBSD and EDX analysis at the cladding - Substrate interface of a laser clad railway wheel N2 - Electron backscatter diffraction and energy-dispersive X-ray spectrometry were used to investigate the intermixed interface produced during laser cladding of a Co-Cr-Mo alloy on a steel substrate. A multi-component system and rapid solidification conditions together lead to a complex microstructure at the interface. The solidification of the cladding starts with the formation of an interface layer, which is about 75µm in thickness and consists of randomly oriented equiaxed grains of Co-Cr-Fe solid solution and martensite. Orientation analysis of the grains in the interface layer revealed that some grains have a special orientation relationship with the former austenite grains in the heat affected zone but the cladding is not formed by epitaxial growth on the substrate. Intermixing of the materials at the interface is providing a strong bond between the substrate and the cladding. For a grain from the interface layer to emerge as columnar grain in the cladding, it was determined that its <001> crystallographic direction is not supposed to deviate more than 25° from the sample normal direction. KW - EBSD KW - Laser cladding KW - Interface KW - Orientation KW - Nishiyama - Wassermann relationship PY - 2006 DO - https://doi.org/10.3139/146.101413 SN - 1862-5282 VL - 97 IS - 11 SP - 1512 EP - 1518 PB - Hanser CY - München AN - OPUS4-14425 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Farooq, M.U. A1 - Klement, U. A1 - Nolze, Gert T1 - The role of alpha- to epsilon-Co phase transformation on strain hardening of a Co-Cr-Mo laser clad N2 - A laser clad Co–Cr–Mo alloy has been analysed by the electron backscatter diffraction (EBSD) technique to examine the microstructural evolution during tensile deformation and to study the role of the evolved microstructure on strain hardening of the clad. The allotropic phase transformation from α- to ε-Co, that did not take place during cooling from the solidification temperature, occurs in the form of a strain-induced transformation during plastic deformation. Combined slip on non-parallel planes in parallel bands of α- and ε-Co prevents the formation of cracks and contributes to the strain hardening of the material. Due to twin formation at intersecting ε-Co bands, {1 1 0 1} planes become almost parallel to {1 1 1} planes of α-Co, and facilitate further glide of dislocations. Owing to the strain-induced transformation of α- to ε-Co, the laser clad Co–Cr–Mo investigated in this study can accommodate high deformation before cracks are formed at the “wavy slip-lines” and the precipitates. KW - Laser clad KW - EBSD KW - Co-Cr-Mo KW - Phase transformation KW - Strain hardening PY - 2007 SN - 0921-5093 SN - 1873-4936 VL - 445-446 SP - 40 EP - 47 PB - Elsevier CY - Amsterdam AN - OPUS4-14465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gunnerek, R. A1 - Soundarapandiyan, G. A1 - Mishurova, T. A1 - Schröder, J. A1 - Bruno, Giovanni A1 - Boykin, J. A1 - Diaz, A. A1 - Klement, U. A1 - Hryha, E.ON T1 - Chemical mechanical polishing of powder bed fusion – laser beam processed 316 L stainless steel N2 - Additive manufacturing via powder bed fusion – laser beam (PBF-LB) enables the fabrication of complex geometries but suffers from inherently rough surfaces and surface tensile residual stresses, both of which can compromise structural integrity, particularly under fatigue loading. To address these limitations, this study investigates chemical mechanical polishing (CMP) as a surface finishing method for improving surface quality and modifying the residual stress state in PBF-LB 316 L stainless steel. The work uniquely examines how scan rotation (0◦ vs. 67◦ rotation) and contour parameters influence CMP effectiveness in material removal, surface smoothing, and subsurface stress redistribution. With a targeted material removal of 110 μm, CMP reduced surface roughness (Sa) by up to 94 %, achieving values as low as 0.7 μm. Microstructural analysis revealed no grain refinement but identified a thin, plastically deformed surface layer. This plastic deformation resulted in the transformation of tensile surface stresses (340 MPa) into beneficial compressive stresses (􀀀 400 MPa), as confirmed by synchrotron X-ray diffraction, which also showed a shift toward isotropic strain distribution. Further, these findings demonstrate that the initial scan strategy influences CMP performance and that CMP can enhance both surface integrity and mechanical reliability without altering the underlying microstructure. This study advances the understanding of how process induced microstructure and surface features affect CMP outcomes, enabling more informed design of post-processing strategies for improved surface integrity and mechanical performance in additively manufactured metals. KW - Residual stress KW - Additive manufacturing KW - Chemical mechanical polishing KW - As-built microstructure KW - Surface roughness KW - Surface finishing KW - Material removal PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640522 DO - https://doi.org/10.1016/j.jmatprotec.2025.119055 SN - 0924-0136/ VL - 345 SP - 1 EP - 12 PB - Elsevier B.V. AN - OPUS4-64052 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -