Mechanical properties and damage characterizations of 3D double-arrowhead auxetic structure with high-relative-density realized via selective laser melting

Pure Copper (Cu) is very difficult to prepare using selective laser melting (SLM) technology. This work successfully prepared the pure Cu with high relative density and high strength by the SLM technology using a surface oxidation treatment. The gas-atomized pure Cu powder was used as the feedstock in this work. Before the SLM process, the pure Cu powder was initially handled using the surface oxidation treatment to coat the powder with an extremely thin layer of Cu2O. The SLMed highly dense specimens contain α-Cu and nano-Cu2O phases. A relationship between the processing parameters (laser power (LP), scanning speed (SS), and hatch space (HS)) and density of Cu alloy in SLM was also investigated. The microstructure of SLMed Cu consists of fine grains with grain sizes ranging from 0.5 to ~30 μm. Tensile testing and detailed microstructural characterization were performed on specimens in the as-SLMed and pure copper state specimens. The mechanical property experiments showed that the specimens prepared by SLM technology containing nano-oxide phases had higher yield strength and tensile strength than that of other SLM-built pure copper. However, the elongation was remarkably decreased compared to other SLM-built pure copper, due to the fine grains and the nano-oxides.

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Selective Laser Melting of 18NI-300 Maraging Steel

Materials ◽

10.3390/ma13194268 ◽

2020 ◽

Vol 13 (19) ◽

pp. 4268 ◽

Cited By ~ 1

Author(s):

Mariusz Król ◽

Przemysław Snopiński ◽

Jiří Hajnyš ◽

Marek Pagáč ◽

Dariusz Łukowiec

Keyword(s):

Relative Density ◽

Maraging Steel ◽

Selective Laser Melting ◽

Aging Treatment ◽

Steel Powder ◽

Process Conditions ◽

Laser Melting ◽

Microstructure Observation ◽

High Relative Density ◽

Wide Range

In the present study, 18% Ni 300 maraging steel powder was processed using a selective laser melting (SLM) technique to study porosity variations, microstructure, and hardness using various process conditions, while maintaining a constant level of energy density. Nowadays, there is wide range of utilization of metal technologies and its products can obtain high relative density. A dilatometry study revealed that, through heating cycles, two solid-state effects took place, i.e., precipitation of intermetallic compounds and the reversion of martensite to austenite. During the cooling process, one reaction took place (i.e., martensitic transformation), which was confirmed by microstructure observation. The improvements in the Rockwell hardness of the analyzed material from 42 ± 2 to 52 ± 0.5 HRC was improved as a result of aging treatment at 480 °C for 5 h. The results revealed that the relative density increased using laser speed (340 mm/s), layer thickness (30 µm), and hatch distance (120 µm). Relative density was found approximately 99.3%. Knowledge about the influence of individual parameters in the SLM process on porosity will enable potential manufacturers to produce high quality components with desired properties.

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Study on Cellular Structures as the Core Architectures of Parts Based on Selective Laser Melting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.538-541.1904 ◽

2012 ◽

Vol 538-541 ◽

pp. 1904-1907 ◽

Cited By ~ 1

Author(s):

Dong Ming Xiao ◽

Yong Qiang Yang ◽

Xu Bin Su ◽

Man Hui Zhang ◽

Di Wang

Keyword(s):

Mechanical Properties ◽

Relative Density ◽

Selective Laser Melting ◽

High Heat ◽

Unit Cell ◽

Cellular Structures ◽

Compression Tests ◽

Laser Melting ◽

The Core ◽

Cell Architecture

Cellular structures exhibit favorable properties for multifunctional applications, such as light weight, high load-bearing combined with high heat exchange capability. This paper is to seek optimal cellular structures as the core architectures of parts manufactured by selective laser melting (SLM) technology, which provides required mechanical properties. Design features for characterizing optimal structural performance are discussed. Some preliminary design rules are developed to improve the manufacturability and the quality of cellular structures, the orientation of strut is designed as ±45° or 90°. Compression tests are also carried out to seek cellular structures of synthetically optimal mechanical properties. Comparing the effects of the unit cell architecture and the relative density on mechanical properties, it reveals that unit cell architecture is dominant rather than the relative density, and the truss lattice with [90°,±45°] structure is the overall best performing among the selected cellular structures.

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The Effects of Selective Laser Melting Process Parameters on Relative Density of the AlSi10Mg Parts and Suitable Procedures of the Archimedes Method

Applied Sciences ◽

10.3390/app9030583 ◽

2019 ◽

Vol 9 (3) ◽

pp. 583 ◽

Cited By ~ 12

Author(s):

Shigang Bai ◽

Nataliya Perevoshchikova ◽

Yu Sha ◽

Xinhua Wu

Keyword(s):

Image Analysis ◽

Relative Density ◽

Selective Laser Melting ◽

Laser Power ◽

Regression Models ◽

Processing Parameters ◽

Response Surfaces ◽

Laser Melting ◽

High Relative Density ◽

Scan Speed

In view of the importance of accurately measuring the relative density of a selective laser melted (SLMed) part for optimizing the selective laser melting (SLM) processing parameters, suitable procedures of the Archimedes method considering the surface-connected cavities were proposed by comparing the results using the Archimedes method with image analysis. The effects of the SLM processing parameters on the relative density of AlSi10Mg were investigated using the proposed procedures of the Archimedes methods and image analysis. Fourteen SLMed samples were produced by different SLM processing parameters according to Doehlert Matrix. The regression models correlating relative density and three SLM processing parameters (laser power, scan speed, and hatching distance) were built and the optimum parameter combination to get a high relative density was obtained. By plotting the response surfaces and contours of the regression models, it was found that the relative densities are both higher at the combination of the higher scan speed, higher power, and lower hatching distance and at the combination of a lower scan speed, a moderate laser power, and a optional hatching distance. It was also found that the parameter of hatching distance is the crucial parameter to get a high relative density and to get high mechanical property.

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