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Study for Combined Wire + Powder Laser Metal Deposition of H11 and Niobium
摘要： Laser additive manufacturing (LAM) has been proved to be a successful technique to fabricate metallic components for a number of industries; for instance, die & mold, forging and cutting tools, and aerospace. It is, however, facing multitude obstacles due to lack of maturity in terms of process knowledge, design, and qualification. This paper deals with parameters’ study and optimization of combined hot-work tool steel wire (H11) and niobium powder (Nb) deposition by laser. The process is closely analysed and compared with as well as without using Nb powder. Especially, the importance of Nb in order to refine the microstructure is discussed while taking into account the microstructure-property relationships of H11.
关键词： Laser additive manufacturing,Niobium (Nb),Hot-work tool steel,Laser metal deposition,H11
更新于2025-09-16 10:30:52
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Microstructural evolution and geometrical properties of TiB2 metal matrix composite protrusions on hot work tool steel surfaces manufactured by laser implantation
摘要： The laser implantation–named technique aims to address the tribological problems frequently seen on tool surfaces during hot stamping. It is based on the creation of elevated dome- or ring-shaped hard structures on the surface of tool steels by a localized dispersing of hard particles. Therefore, a combination of the two distinct approaches that are normally used in surface technology for optimizing friction and wear, i.e., surface texturing and surface material optimization, are realized in one processing step. In experimental studies, a localized dispersing of TiB2 particles in the surface layer of the hot work tool steel X38CrMoV5-3 was considered and compared with punctual laser–remelted textures. The structures (micro-) hardness was measured at top- and cross-sections. With the aid of a scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction the interaction between the hard particles and the substrate material were studied. From the results, an optimal parameter range was identified for laser implantation. To the investigation’s end, the implant geometry was measured by optical microscopy and white light microscopy. Furthermore, a mathematic model was introduced, which allows a prediction of the implant geometry as a response to the laser parameters. It was shown that the implantation of TiB2 particles leads to a significant hardness increase up to 1600 HV1 due to the dispersion of initial particles and an in situ precipitation of new titanium-rich phases. It was possible to create defect-free dome- and ring-shaped microstructures on the surfaces. It was also shown that the implants geometry highly depends on the applied laser parameters. The applied central composite design shows a good agreement with the experimental results.
关键词： TiB2,Laser implantation,Localized laser dispersing,Hot stamping,Surface texturing,Hot work tool steel
更新于2025-09-12 10:27:22
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Additive manufacturing of tool steel by laser metal deposition
摘要： In this work, different geometries were additively manufactured applying laser metal deposition using powder out of hot-working tool steel 1.2344. It was shown that this hot working tool steel can be used to manufacture crack free parts through laser metal deposition. Temperatures were locally measured in experimental investigations. Additional microstructure analysis of different geometries indicated a dendritic solidification structure and grain boundary carbides. Vickers hardness varied between 400 HV 1 and 750 HV 1.
关键词： intrinsic heat treatment,1.2344,additive manufacturing,laser metal deposition,hot work tool steel,dilatometer specimen
更新于2025-09-12 10:27:22
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Fracture Toughness of a Hot Work Tool Steel Fabricated by Laser‐Powder Bed Fusion Additive Manufacturing
摘要： The fracture toughness of AISI H13 tool steel, additively manufactured by laser powder bed fusion (L-PBF) technique was studied. The influence of the building direction on fracture toughness was investigated on small notched bending samples heat treated according to two different thermal cycles, namely quenching and tempering (QT) and only tempering (T). The notch was electro discharge machined parallel (P//), perpendicular (P┴) and longitudinal (L) to the building direction. Both heat treatments, even if to a different extent, delete the as-built microstructure, producing secondary carbides precipitation in the martensitic matrix. The microstructure of the directly tempered parts is finer than the quenched and tempered ones. The fracture toughness increases moving from P┴ to P//. The T samples show a higher apparent fracture toughness in the P//, despite the higher hardness. Secondary cracks formation allows toughness in P// samples. This effect is more pronounced in T samples where the stronger precipitation of carbides at the prior melt boundaries promotes secondary cracks. Moreover, in P// samples the laser tracks act as barriers to crack propagation and as stress dissipators.
关键词： Laser powder bed fusion,hot work tool steel,fracture toughness,microstructure
更新于2025-09-12 10:27:22