Surface integrity of Inconel 718 by hybrid selective laser melting and milling

Brown, Donald W.; Li, C.; Liu, Z. Y.; Fang, Xiaojun; Guo, Y. B.

doi:10.1080/17452759.2017.1392681

Cited by 45 publications

(9 citation statements)

References 11 publications

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“…Generally, the balling effect is a typical metallurgical defect in the SLM process, which closely related to the temperature of the liquid phase, wetting ability and Marangoni convection [31,32]. At a high scan speed, the laser tracks easily show a shrinking trend for reducing the surface tension due to the poor wetting characteristic.…”

Section: Densification Behavior and Metallurgical Defect Analysismentioning

confidence: 99%

Effect of Trace Addition of Ceramic on Microstructure Development and Mechanical Properties of Selective Laser Melted AlSi10Mg Alloy

Zhang

et al. 2020

Chin. J. Mech. Eng.

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Selective laser melting (SLM) is an emerging additive manufacturing technology for fabricating aluminum alloys and aluminum matrix composites. Nevertheless, it remains unclear how to improve the properties of laser manufactured aluminum alloy by adding ceramic reinforcing particles. Here the effect of trace addition of TiB 2 ceramic (1% weight fraction) on microstructural and mechanical properties of SLM-produced AlSi10Mg composite parts was investigated. The densification level increased with increasing laser power and decreasing scan speed. A near fully dense composite part (99.37%) with smooth surface morphology and elevated inter-layer bonding was successfully obtained. A decrease of lattice plane distance was identified by X-ray diffraction with the laser scan speed decreased, which implied that the crystal lattices were distorted due to the dissolution of Si and TiB 2 particles. A homogeneous composite microstructure with the distribution of surface-smoothened TiB 2 particles was present, and a small amount of Si particles precipitated at the interface between reinforcing particles and matrix. In contrast to the AlSi10Mg alloy, the composites showed a stabilized microhardness distribution. A higher ultimate tensile strength of 380.0 MPa, yield strength of 250.4 MPa and elongation of 3.43% were obtained even with a trace amount of ceramic addition. The improvement of tensile properties can be attributed to multiple mechanisms including solid solution strengthening, load-bearing strengthening and dispersion strengthening. This research provides a theoretical basis for ceramic reinforced aluminum matrix composites by additive manufacturing.

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Section: Densification Behavior and Metallurgical Defect Analysismentioning

confidence: 99%

Effect of Trace Addition of Ceramic on Microstructure Development and Mechanical Properties of Selective Laser Melted AlSi10Mg Alloy

Zhang

et al. 2020

Chin. J. Mech. Eng.

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“…In recent years, additive manufacturing (AM) of these alloys from powder material by using powder bed fusion (PBF) processes such as selective laser sintering (SLS), electron beam melting (EBM) and selective laser melting (SLM) have been adopted to fabricate products to increase flexibility and reduce the production cost [5,6]. Although AM technologies can result in a near net-shape geometry for additively manufactured parts, finish machining processes are still needed to achieve desired surface finish and dimensional tolerances [7][8][9][10][11]. Therefore, machinability of additively manufactured titanium-based alloys and nickel-based superalloys has gained attention recently from the research community.…”

Section: Introductionmentioning

confidence: 99%

Effects of Machining Parameters on Finishing Additively Manufactured Nickel-Based Alloy Inconel 625

Fei

Liu

Patel

et al. 2020

JMMP

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Metal additive manufacturing processes such as selective laser melting (SLM), laser powder bed fusion (L-PBF), electron beam melting (EBM) and laser metal deposition (LMD) can produce additively manufactured nearly fully dense parts with high geometrical complexity. These are often used as components in automotive, aerospace and medical device industries. Finish machining of these components is required to achieve the desired surface finish and dimensional tolerances. The investigations on additively manufactured alloys, as reported in the literature, indicate that a layer-wise scan strategy (orthogonal or layer-to-layer rotation) and process parameters have significant influences on the resultant microstructure which affects the final mechanical properties and fatigue life. The solidification microstructure depicts that growth directions of columnar grains and sizes of cellular grains that are affected by the layer-wise scan strategy. This paper presents experimental investigations on finish milling parameters on a nickel-based alloy manufactured with L-PBF using two distinct layer-wise scan strategies. The results reveal some effects of milling direction against the layer-wise build direction. The effects of cutting speed and feed rate on resultant cutting forces, chip formation, as well as surface finish at various cutting orientations in nickel-based alloy workpieces are reported.

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“…There are various techniques used for additive manufacturing technologies, especially threedimensional printing to form three-dimensional geometries. For instance, selective laser melting (SLM) which uses a highenergy laser beam to melt the metal powder, which will induce porosity and stresses in the work part if a proper environment is not adopted (Yap et al, 2016;Wong et al, 2016;Brown et al, 2018). It usually forms three-dimensional parts from point-toline and then from line-to-surface (Shuzhen et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

An improved medial axis path generation algorithm for selective laser melting

Zhang

Ding

Ullah

et al. 2020

RPJ

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Purpose The principle of the medial axis calculation is complicated and difficult to implement. Moreover, the accuracy is not high. Then, as the generated path has an endpoint at the boundary of the polygon, burrs may appear on the surface of the molded piece. This paper aims to improve the warpage deformation of SLM molded parts and the surface quality of molded parts, an improved mid-axis path generation algorithm is proposed. Design/methodology/approach First, the center point is calculated by the seed point growth method based on the distance transform, and the obtained medial axis has high precision and is suitable for simple polygons and complex polygons. Then, based on the extracted medial axis, a preliminary path is generated, the path is trimmed with MATLAB to remove the redundant path. Finally, a scan along the contour of the polygon is performed to improve the surface quality of the molded part. Findings The algorithm reduces the internal stress generated during the molding process by continuously changing the scanning direction of the path along the boundary curve of the scanning area, thereby reducing the amount of warpage of the molded part. The result of extraction has a higher precision and wider scope of application than other methods to extract central axis, such as the Voronoi diagram-based method. The path is trimmed to remove redundant paths and the polygon boundaries are scanned to further improve the surface quality of the molded part. The results show that warpage deformation of the proposed algorithm is significantly smaller than the other two methods, thus the forming precision is higher. Originality/value An improved medial axis path generation algorithm is proposed in this paper. The proposed method is applied to improve warpage deformation occurring in the SLM process. Seed point growth of distance transformation is used to extracted central axis. The result of extraction has a higher precision and wider scope of application than other methods to extract central axis, such as the Voronoi diagram-based method.

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Surface integrity of Inconel 718 by hybrid selective laser melting and milling

Cited by 45 publications

References 11 publications

Effect of Trace Addition of Ceramic on Microstructure Development and Mechanical Properties of Selective Laser Melted AlSi10Mg Alloy

Effect of Trace Addition of Ceramic on Microstructure Development and Mechanical Properties of Selective Laser Melted AlSi10Mg Alloy

Effects of Machining Parameters on Finishing Additively Manufactured Nickel-Based Alloy Inconel 625

An improved medial axis path generation algorithm for selective laser melting

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