Research on the processing experiments of laser metal deposition shaping

Zhang, Kai; Liu, Weijun; Shang, Xiaobang

doi:10.1016/j.optlastec.2005.10.009

Cited by 195 publications

(106 citation statements)

References 9 publications

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“…4 demonstrates the X-ray diffraction result of the welded seam, from which it could be found that in the whole region of the welded seam, the peak of {1 1 1}, {2 0 0} and {3 1 1} orientations was quite evident, which manifested that in the central region of the welded seam, the growing directions of grains were rather disorderly, and the solidification microstructure was not the directional solidification dendrite any longer. Other authors [15] found the similar microstructure features in laser metal deposition shaping (LMDS)-fabricated parts, with the decreasing of the G/V s , the microstructures of the laser cladding layer gradually changed from nearly parallel dendrites to the fine-equiaxed grains.…”

Section: Microstructure Examinationsmentioning

confidence: 67%

“…7c, which clearly exhibited the debonding along phase (or particle) boundaries, showing a typical intercrystalline fracture. This kind of diverse types of fracture often occurs to the materials with high strength and fine ductility [15]. The appearance of dendritic pattern on the weld fracture surface also indicated that the fracture had taken place preferentially along the interdendritic regions.…”

Section: The Mechanical Properties Of the Laser Welding Seammentioning

confidence: 99%

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Research on laser welding of cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft

Liu

Guo

et al. 2008

Journal of Alloys and Compounds

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Exploratory experiments of laser welding cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft were conducted. Microstructure of the welded seam was characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), energydispersive spectrometer (EDS). Mechanical properties of the welded seam were evaluated by microhardness and tensile strength testing. The corresponding mechanisms were discussed in detail. Results showed that the laser-welded seam had non-equilibrium solidified microstructures consisting of FeCr 0.29 Ni 0.16 C 0.06 austenite solid solution dendrites as the dominant and some fine and dispersed Ni 3 Al ␥ phase and Laves particles as well as little amount of MC short stick or particle-like carbides distributed in the interdendritic regions. The average microhardness of the welded seam was relatively uniform and lower than that of the base metal due to partial dissolution and suppression of the strengthening phase ␥ to some extent. About 88.5% tensile strength of the base metal was achieved in the welded joint because of a non-full penetration welding and the fracture mechanism was a mixture of ductility and brittleness. The existence of some Laves particles in the welded seam also facilitated the initiation and propagation of the microcracks and microvoids and hence, the detrimental effects of the tensile strength of the welded joint. The present results stimulate further investigation on this field.

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Section: Microstructure Examinationsmentioning

confidence: 67%

Section: The Mechanical Properties Of the Laser Welding Seammentioning

confidence: 99%

Research on laser welding of cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft

Liu

Guo

et al. 2008

Journal of Alloys and Compounds

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“…Welding technology such as laser welding or arc welding is used for this purpose. Most equipment commercially available today uses special nozzles to distribute powder into a laser beam to be melted; Direct Light Fabrication (DLF) , Selective Laser Melting (SLM) (Bertrand and Smurov 2007), Laser Metal Deposition Shaping (Zhang et al 2007), and the LENS-system (Wang and Felicelli 2006;Wu and Mei 2003). Robotised Laser Metal wire Deposition (RLMwD) (Heralic et al 2008), Shaped Metal Deposition (SMD) (EscobarPalafox et al 2011;Rooks 2005), Wire and arc additive manufacturing (WAAM) (Wang et al 2012) or Robotised TIG Metal wire Deposition (RTMwD) are examples of wire-feed metal deposition processes.…”

Section: Near-net-shape Manufacturing and Metal Depositionmentioning

confidence: 99%

A model for Ti–6Al–4V microstructure evolution for arbitrary temperature changes

Murgau

Pederson

Lindgren

2012

Modelling Simul. Mater. Sci. Eng.

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This thesis is devoted to microstructure modelling of Ti-6Al-4V. The microstructure and the mechanical properties of titanium alloys are highly dependent on the temperature history experienced by the material. The developed microstructure model accounts for thermal driving forces and is applicable for general temperature histories. It has been applied to study wire feed additive manufacturing processes that induce repetitive heating and cooling cycles. The microstructure model adopts internal state variables to represent the microstructure through microstructure constituents' fractions in finite element simulation. This makes it possible to apply the model efficiently for large computational models of general thermomechanical processes. The model is calibrated and validated versus literature data. It is applied to Gas Tungsten Arc Welding -also known as Tungsten Inert Gas welding-wire feed additive manufacturing process. Four quantities are calculated in the model: the volume fraction of phase, consisting of Widmanstätten , grain boundary , and martensite . The phase transformations during cooling are modelled based on diffusional theory described by a Johnson-Mehl-AvramiKolmogorov formulation, except for diffusionless martensite formation where the Koistinen-Marburger equation is used. A parabolic growth rate equation is used for the to transformation upon heating. An added variable, structure size indicator of Widmanstätten , has also been implemented and calibrated. It is written in a simple Arrhenius format. The microstructure model is applied to in finite element simulation of wire feed additive manufacturing. Finally, coupling with a physically based constitutive model enables a comprehensive and predictive model of the properties that evolve during processing.

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“…Higher scanning velocity means less material in the melt pool which leads to narrower tracks. Higher laser power density creates a wider deposition track [45]. The ratio between the width and the height of a single deposit track is an important design factor from which the process parameters quickly can be assessed.…”

Section: Bead Geometrymentioning

confidence: 99%

Review of Laser Deposited Superalloys Using Powder as an Additive

Segerstark¹,

Andersson²,

Svensson³

2014

8th International Symposium on Superalloy 718 and Derivatives (2014)

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In this paper laser metal deposition (LMD) with blown powder was reviewed with respect to the material behavior of nickel and nickel-iron based superalloys. The key benefits of LMD are claimed to be increased design freedom of components as well as reduced environmental impact since it enables near net shape manufacturing. This review considers the LMD processing parameters such as laser power, powder feed rate, spot size, standoff distance, and traverse speed, together with aspects related to the powder e.g. morphology, porosity, inclusion and satellite content. Special emphasis was put on how these parameters affect the deposit and substrate in terms of cracking, porosity, inclusions, phase transformations, and other material related phenomena. A characteristic microstructure of LMD deposited superalloys has a columnar dendrite growth in the vertical build up direction. The grain growth can however be manipulated, making it more equiaxed by, for instance, altering process parameters and/or scanning path. Residual stresses in LMD samples are unevenly distributed and large residual tensile stresses can be found at the surface of the deposit while large compressive stresses are located close to the substrate in the core of the deposit. One of the most important parameter is considered to be the specific energy input which largely influences the m elt pool during deposition which in turn can be related to the microstructure, residual stress and, process related defects such as porosity, cracking, lack of fusion and, dilution.

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Research on the processing experiments of laser metal deposition shaping

Cited by 195 publications

References 9 publications

Research on laser welding of cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft

Research on laser welding of cast Ni-based superalloy K418 turbo disk and alloy steel 42CrMo shaft

A model for Ti–6Al–4V microstructure evolution for arbitrary temperature changes

Review of Laser Deposited Superalloys Using Powder as an Additive

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