scholarly journals Mechanical characterization and properties of laser-based powder bed–fused lattice structures: a review

2021 ◽  
Author(s):  
Leonardo Riva ◽  
Paola Serena Ginestra ◽  
Elisabetta Ceretti
Keyword(s):  
Mechanical Properties ◽  
Mechanical Characterization ◽  
Lattice Structure ◽  
Mechanical Test ◽  
Wide Spectrum ◽  
Lattice Structures ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Metal Lattice

AbstractThe increasing demand for a wider access to additive manufacturing technologies is driving the production of metal lattice structure with powder bed fusion techniques, especially laser-based powder bed fusion. Lattice structures are porous structures formed by a controlled repetition in space of a designed base unit cell. The tailored porosity, the low weight, and the tunable mechanical properties make the lattice structures suitable for applications in fields like aerospace, automotive, and biomedicine. Due to their wide-spectrum applications, the mechanical characterization of lattice structures is mostly carried out under compression tests, but recently, tensile, bending, and fatigue tests have been carried out demonstrating the increasing interest in these structures developed by academy and industry. Although their physical and mechanical properties have been extensively studied in recent years, there still are no specific standards for their characterization. In the absence of definite standards, this work aims to collect the parameters used by recent researches for the mechanical characterization of metal lattice structures. By doing so, it provides a comparison guide within tests already carried out, allowing the choice of optimal parameters to researchers before testing lattice samples. For every mechanical test, a detailed review of the process design, test parameters, and output is given, suggesting that a specific standard would enhance the collaboration between all the stakeholders and enable an acceleration of the translation process.

On the manufacturability of Inconel 718 thin-walled honeycomb structures by laser powder bed fusion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
José M. Zea Pérez ◽  
Jorge Corona-Castuera ◽  
Carlos Poblano-Salas ◽  
John Henao ◽  
Arturo Hernández Hernández
Keyword(s):  
Mechanical Properties ◽  
Inconel 718 ◽  
Dimensional Accuracy ◽  
Honeycomb Lattice ◽  
Lattice Structures ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Content Type ◽  
Powder Bed ◽  
Thin Walled

Purpose The purpose of this paper is to study the effects of printing strategies and processing parameters on wall thickness, microhardness and compression strength of Inconel 718 superalloy thin-walled honeycomb lattice structures manufactured by laser powder bed fusion (L-PBF). Design/methodology/approach Two printing contour strategies were applied for producing thin-walled honeycomb lattice structures in which the laser power, contour path, scanning speed and beam offset were systematically modified. The specimens were analyzed by optical microscopy for dimensional accuracy. Vickers hardness and quasi-static uniaxial compression tests were performed on the specimens with the least difference between the design wall thickness and the as built one to evaluate their mechanical properties and compare them with the counterparts obtained by using standard print strategies. Findings The contour printing strategies and process parameters have a significant influence on reducing the fabrication time of thin-walled honeycomb lattice structures (up to 50%) and can lead to improve the manufacturability and dimensional accuracy. Also, an increase in the young modulus up to 0.8 times and improvement in the energy absorption up to 48% with respect to those produced by following a standard strategy was observed. Originality/value This study showed that printing contour strategies can be used for faster fabrication of thin-walled lattice honeycomb structures with similar mechanical properties than those obtained by using a default printing strategy.

scholarly journals Position-dependent mechanical characterization of the PBF-EB-manufactured Ti6Al4V alloy

2021 ◽  
Author(s):  
Daniel Kotzem ◽  
Alexandra Höffgen ◽  
Rajevan Raveendran ◽  
Felix Stern ◽  
Kerstin Möhring ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Material Properties ◽  
Mechanical Characterization ◽  
Industrial Applications ◽  
Fatigue Tests ◽  
Ti6al4v Alloy ◽  
Effective Diameter ◽  
Powder Bed Fusion ◽  
Powder Bed

AbstractBy means of additive manufacturing, the production of components with nearly unlimited geometrical design complexity is feasible. Especially, powder bed fusion techniques such as electron beam powder bed fusion (PBF-EB) are currently focused. However, equal material properties are mandatory to be able to transfer this technique to a wide scope of industrial applications. Within the scope of this work, the mechanical properties of the PBF-EB-manufactured Ti6Al4V alloy are investigated as a function of the position on the building platform. It can be stated that as-built surface roughness changes within building platform whereby highest surface roughness detected by computed tomography (Ra = 46.0 ± 5.3 µm) was found for specimens located in the front of the building platform. In contrast, no significant differences in relative density could be determined and specimens can be assumed as nearly fully dense (> 99.9%). Furthermore, all specimens are affected by an undersized effective diameter compared to the CAD data. Fatigue tests revealed that specimens in the front of the building platform show slightly lower performance at higher stress amplitudes as compared to specimens in the back of the building platform. However, process-induced notch-like defects based on the surface roughness were found to be the preferred location for early crack initiation.

scholarly journals Mechanical Properties and In-Situ Deformation Imaging of Micro-Lattices Manufactured by Laser Based Powder Bed Fusion

2018 ◽  
Author(s):  
Anton Du Plessis ◽  
Dean-Paul Kouprianoff ◽  
Ina Yadroitsava ◽  
Igor Yadroitsev
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Lattice Structures ◽  
Powder Bed Fusion ◽  
Track Width ◽  
Powder Bed ◽  
Deformation Imaging ◽  
Small Pore ◽  
In Situ Deformation

This paper reports on the production and mechanical properties of Ti6Al4V micro-lattice structures, with strut thickness nearing the single-track width of the laser-based powder bed fusion (LPBF) system used. Besides providing new information on the mechanical properties and manufacturability of such thin-strut lattices, this paper also reports on the in-situ deformation imaging of micro-lattice structures with 6 unit cells in every direction. LPBF lattices are of interest for medical implants, due to the possibility of creating structures with an elastic modulus close to that of the bones and small pore sizes which allow effective osseointegration. In this work four different cubes were produced by laser powder bed fusion and subsequently analyzed using microCT, compression testing and one selected lattice was subjected to in-situ microCT imaging during compression. The in-situ imaging was performed at 4 steps during yielding. The results indicate that mechanical performance (elastic modulus and strength) correlate well with actual density and that this performance is remarkably good, despite the high roughness and irregularity of the struts at this scale. In-situ yielding is visually illustrated.

scholarly journals Compressive Properties of Al-Si Alloy Lattice Structures with Three Different Unit Cells Fabricated via Laser Powder Bed Fusion

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2902 ◽  
Author(s):  
Xiaoyang Liu ◽  
Keito Sekizawa ◽  
Asuka Suzuki ◽  
Naoki Takata ◽  
Makoto Kobashi ◽  
...  
Keyword(s):  
Strain Rate ◽  
Lattice Structure ◽  
Unit Cell ◽  
Lattice Structures ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Compressive Properties ◽  
Powder Bed ◽  
Unit Cells ◽  
Indentation Tests

In the present study, in order to elucidate geometrical features dominating deformation behaviors and their associated compressive properties of lattice structures, AlSi10Mg lattice structures with three different unit cells were fabricated by laser powder bed fusion. Compressive properties were examined by compression and indentation tests, micro X-ray computed tomography (CT), together with finite element analysis. The truncated octahedron- unit cell (TO) lattice structures exhibited highest stiffness and plateau stress among the studied lattice structures. The body centered cubic-unit cell (BCC) and TO lattice structures experienced the formation of shear bands with stress drops, while the hexagon-unit cell (Hexa) lattice structure behaved in a continuous deformation and flat plateau region. The Hexa lattice structure densified at a smaller strain than the BCC and TO lattice structures, due to high density of the struts in the compressive direction. Static and high-speed indentation tests revealed that the TO and Hexa exhibited slight strain rate dependence of the compressive strength, whereas the BCC lattice structure showed a large strain rate dependence. Among the lattice structures in the present study, the TO lattice exhibited the highest energy absorption capacity comparable to previously reported titanium alloy lattice structures.

scholarly journals Development of individual medical implants with specific mechanical properties manufactured by Laser Powder Bed Fusion

10.29007/f8gt ◽  
2020 ◽  
Author(s):  
Johannes Willkomm ◽  
Lucas Jauer ◽  
Stephan Ziegler ◽  
Johannes Henrich Schleifenbaum
Keyword(s):  
Medical Technology ◽  
Lattice Structure ◽  
Automated Design ◽  
Patient Data ◽  
Vertebral Body Replacement ◽  
Lattice Structures ◽  
Powder Bed Fusion ◽  
Compression Tests ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

Laser Powder Bed Fusion (LPBF) is an additive manufacturing process, which enables the generation of complex geometries such as lattice structures, using metallic powder. Lattice structures are being used increasingly in medical technology to adapt the stiffness of individualized implants which can lead to faster bone healing. Lattice structures are also used to adjust the contact surface between the bone and implant to adapt the osseointegrative behavior. The goal of this work is to create lattice structures with local adaption of the stiffness (modulus of elasticity) for individual vertebral body replacement implants and their automated design based on patient data.To form the lattice structure a diamond cell type is used, which is common in medical technology. For the later adaptation of the bone stiffness, the stiffness of the lattice structure with different strut diameters are determined. The calculation of the stiffness is done by numerical simulations using Finite Element Methods (FEM). The simulations are validated with tensile and compression tests. Finally, the automated design of the implants is carried out with an in-house generated tool to adjust the strut diameters based on the bone density from patient data.Parts of this work have been funded by the German ministry of education and research (BMBF) under grant number 13GW0116.

Microstructural and Mechanical Characterization of Aluminum Matrix Composites Produced by Laser Powder Bed Fusion

2017 ◽  
Vol 19 (11) ◽  
pp. 1700180 ◽  
Author(s):  
Alberta Aversa ◽  
Giulio Marchese ◽  
Massimo Lorusso ◽  
Flaviana Calignano ◽  
Sara Biamino ◽  
...  
Keyword(s):  
Mechanical Characterization ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed
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