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Effect of Inter-Layer Dwell Time on Distortion and Residual Stresses of Laser Metal Deposited Wall
摘要： The laser metal deposition is an advanced manufacturing technology enabling the production of large-sized parts and partially or completely elimination of machining and welding. The process is characterised by a non-uniform local heating of the buildup leading to a stress distribution, which may exceed the yield strength of the material and leads to loss of dimensional accuracy. The interlayer dwell time has a strong influence on the temperature field. The effect of the interlayer dwell time on the distortion and the stress distribution during laser metal deposition of a single-pass wall on the edge of 2 mm thick plate was studied experimentally and numerically. The deposited material was IN625 and the substrate material was AISI 316. A decrease of the residual displacement, due to a uniform shrinkage after the deposition of the last layer and a lower level of the residual compressive longitudinal plastic strain, has been observed in the studies without a dwell time. The peak increment of the free edge displacement corresponds to the first layer and hence the subsequent layers will be deposited on the already plastically deformed buildup. The tensile residual longitudinal stress near the top of the buildup and transverse stress near the edges of the buildup is higher than yield strength in the studies with dwell time.
关键词： Temperature field,Laser metal deposition,Residual stresses,Simulation,Distortion
更新于2025-09-16 10:30:52
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Application of Laser Metal Deposition for a New Model of Assembled Camshaft
摘要： This work introduces the invention of an alternative camshaft manufacturing method aimed at improving the efficiency of the process and providing a more flexible product. The innovation consists in the laser metal deposition (LMD) of a profile on the shaft in order to realize a coupling stretch where the cam is fixed by interference. Alternative profile materials (1.4404 steel and Inconel 625 alloy) are deposited on a 1.0421 steel tube at different laser power levels and powder flow rate. The effect of the process parameters on the deposited profile is investigated initially through the evaluation of indirect quality attributes, such as deposit dimensions, hardness values, and microstructure. Then, the coupling force resulting from the press-fit test is evaluated. Finally, the best configuration of this new assembled camshaft is tested with a torsion test rig. Performances of the new assembled camshaft are compared with those of traditional products, leading to the validation of this innovative solution. The preliminary feasibility of the LMD application to the production of an assembled camshaft is demonstrated.
关键词： additive manufacturing,cladding,hardness,testing,laser metal deposition (LMD),dilution
更新于2025-09-16 10:30:52
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Design and optimization of discrete powder nozzle for laser metal deposition
摘要： For design and optimization of discrete powder nozzle for laser metal deposition the experimental research was completed. Influence of powder jet geometry, of powder streams interaction and influence of shield gas at powder efficiency was investigated. The prototype of discrete powder nozzle was designed. Experimentally defined, that powder jet with inner diameter 1.4 mm and length 60 mm provide the highest powder efficiency for discrete powder nozzle. Interaction of gas-powder streams causes a decrease of powder efficiency. Shield gas using doesn’t affect powder efficiency of discrete powder nozzle.
关键词： laser metal deposition,powder efficiency,interaction of powder stream,coaxial discrete nozzle,powder nozzles,Additive manufacturing
更新于2025-09-16 10:30:52
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[Laser Institute of America ICALEO? 2016: 35th International Congress on Applications of Lasers & Electro-Optics - San Diego, California, USA (October 16–20, 2016)] International Congress on Applications of Lasers & Electro-Optics - LMD process diagrams for blade tip repair
摘要： Laser Metal Deposition (LMD) is a technology often used for local repairs of e.g. high quality and high value its specific turbomachinery components. Due advantages such as low heat input into the work piece, low distortion, high reproducibility and the suitability for automation, LMD is especially used for blade tip-repair. In general, existing repair processes and results cannot be transferred to new repair applications without substantial adaptations. The development of new tip repair processes strongly depends on the part geometry and the specific materials. For the development of a new tip repair application, the LMD process parameters – such as laser power, scanning speed, powder mass flow as well as beam diameter – have to be adapted and require intensive experimental work. Although this approach is still state of the art, it is time consuming and cost intensive. LMD process diagrams can significantly reduce those experimental efforts and shorten the development time for new repair applications.
关键词： process diagrams,blade tip repair,Laser Metal Deposition,turbomachinery components,LMD
更新于2025-09-16 10:30:52
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Influence of adaptive slice thickness and retained heat effect on laser metal deposited thin-walled freeform structures
摘要： Light-weight, thin-walled freeform structures of aerospace materials can be realized through Additive Manufacturing process like powder- and wire-based Laser Metal Deposition (LMD) technique. Repeatability, in the context of deposited clad geometry and achieved microstructure hinders the wide-spread industrialization of high deposition rate LMD process, which is influenced by numerous intrinsic and extrinsic process parameters. In this paper, the influences of adaptive slice thickness and retained heat effect on build geometry and microstructure have been investigated. Experiments carried out with a powder-fed LMD system to build Ti-6Al-4V freeform structures have been examined for geometrical accuracy and microstructure analysis.
关键词： Layer-to-layer control,High deposition rate,Adaptive slice thickness,Retained heat effect,Laser Metal Deposition
更新于2025-09-12 10:27:22
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Fabrication of Metal Matrix Composite by Laser Metal Deposition—A New Process Approach by Direct Dry Injection of Nanopowders
摘要： Laser Metal Deposition (LMD) offers new perspectives for the fabrication of metal matrix nanocomposites (MMnCs). Current methods to produce MMnCs by LMD systematically involve the premixing of the nanopowders and the micropowders or require in-situ strategies, thereby restricting the possibilities to adjust the nature, content and location of the nano-reinforcement during printing. The objective of this study is to overcome such restrictions and propose a new process approach by direct injection of nanoparticles into a metallic matrix. Alumina (n-Al2O3) nanoparticles were introduced into a titanium matrix by using two different direct dry injection modes in order to locally increase the hardness. Energy dispersive X-ray spectroscopy (EDS) analyses validate the successful incorporation of the n-Al2O3 at chosen locations. Optical and high resolution transmission electron microscopic (HR-TEM) observations as well as X-ray diffraction (XRD) analyses indicate that n-Al2O3 powders are partly or totally dissolved into the Ti melted pool leading to the in-situ formation of a composite consisting of fine α2 lamellar microstructure within a Ti matrix and a solid solution with oxygen. Mechanical tests show a significant increase in hardness with the increase of injected n-Al2O3 amount. A maximum of 620 HV was measured that is almost 4 times higher than the pure LMD-printed Ti structure.
关键词： laser metal deposition,solid solution,direct nanopowder injection,lamellar microstructure,hardness,titanium aluminide,metal matrix composite
更新于2025-09-12 10:27:22
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Laser-plasma-cladding as a hybrid metal deposition-technology applying a SLM-produced copper plasma nozzle
摘要： Laser-Metal-Deposition (LMD) and Plasma-Transferred-Arc (PTA) are well known technologies which can be used for cladding purposes. The prime objective in combining LMD and PTA as a Hybrid Metal Deposition-Technology (HMD) is to achieve high deposition rates at low thermal impact. Possible applications are coatings for wear protection or repair welding for components made of steel. The two energy sources (laser and plasma arc) build a joint process zone and are configurated to constitute a stable process at laser powers between 0.4-1 kW (defocused) and plasma currents between 75-200 A. Stainless steel 316L serves as filler material. For this HMD process, a plasma Cu-nozzle is designed and produced by powder bed based Selective Laser Melting. The potential of the HMD technology is investigated and discussed considering existing processes. This paper demonstrates how the interaction of the two energy sources effects the following application-relevant properties: deposition rate, powder efficiency and energy input.
关键词： Laser-Plasma-Hybrid,Laser-Metal-Deposition,SLM printed plasma torch,Plasma-Transferred-Arc
更新于2025-09-12 10:27:22
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Embedding electronics into additive manufactured components using laser metal deposition and selective laser melting
摘要： The paper deals with the integration of a light emitting diode (LED) into an additive manufactured metal component. Selective laser melting (SLM) and laser metal deposition (LMD) are used. The material used is the chrome-nickel steel 316L. The basic component is manufactured by means of SLM and consists of a solid body and an area with grid structure. The solid body includes a duct in the shape of a groove with a recess for the positioning of the power cable. The LED is embedded in the grid structure via an inlet from the solid body. In further processing, the groove is filled with LMD. Two strategies with different parameter combinations were investigated. It shows that a high energy input near the power cable leads to its destruction. By using multiple parameter combinations during the manufacturing process, this destruction can be prevented. There was a comparison of both strategies with regard to the necessary number of tracks and duration of welding time.
关键词： condition monitoring,embedded electronics,additive manufacturing,laser-metal-deposition,selektive-laser-melting,process chain
更新于2025-09-12 10:27:22
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Parameter development and characterization of laser metal deposited Ti alloy powders for use at elevated temperatures
摘要： Powder-based laser metal deposition (LMD) of Ti alloys enables the manufacturing of geometrical complex structures with tailored properties for high-temperature applications. The most important parameters for the LMD-process are the laser power, process velocity, laser focus position, gas flow and powder feed rate. Compared to the predominantly used Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo shows a higher oxidation resistance and a lower creep rate. For determining suitable process conditions, a parameter study using Ti-6Al-2Sn-4Zr-2Mo powder is performed. Subsequent, the parameter transfer to a γ-TiAl alloy is examined. The assessment of the dissimilar-LMD-structures is conducted by visual inspection, radiography inspection, microstructural analysis and hardness measurements.
关键词： fiber laser,γ-TiAl,laser metal deposition,microstructure characterization,Ti alloy
更新于2025-09-12 10:27:22
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Comparison of laser metal deposition of Inconel 718 from powder, hot and cold wire
摘要： The present paper details first results on laser metal deposition with a new direct diode laser head which allows for coaxial feed of powder, cold- and hot wire material in a single system. The three process variants are compared for laser metal deposition of Inconel 718. The surface appearance, integrity and microstructure of the specimens built with the LMD head are investigated. The presence and removal of the deleterious Laves phase which is detrimental to the mechanical properties is investigated. The results indicate that the new diode laser head allows for a direction-independent LMD process with low oxygen take-up and high surface quality.
关键词： nickel superalloy,Laves phase,direct diode laser,Laser metal deposition
更新于2025-09-12 10:27:22