scholarly journals Microstructural and Tensile Properties Anisotropy of Selective Laser Melting Manufactured IN 625

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4829
Author(s):  
Mihaela Raluca Condruz ◽  
Gheorghe Matache ◽  
Alexandru Paraschiv ◽  
Tiberius Florian Frigioescu ◽  
Teodor Badea
Keyword(s):  
Tensile Properties ◽  
Selective Laser Melting ◽  
Experimental Investigations ◽  
Vertical Position ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Specimen Orientation ◽  
Mechanical Performances ◽  
Scanning Strategies ◽  
Microstructural Anisotropy

The present study was focused on the assessment of microstructural anisotropy of IN 625 manufactured by selective laser melting (SLM) and its influence on the material’s room temperature tensile properties. Microstructural anisotropy was assessed based on computational and experimental investigations. Tensile specimens were manufactured using four building orientations (along Z, X, Y-axis, and tilted at 45° in the XZ plane) and three different scanning strategies (90°, 67°, and 45°). The simulation of microstructure development in specimens built along the Z-axis, applying all three scanning strategies, showed that the as-built microstructure is strongly textured and is influenced by the scanning strategy. The 45° scanning strategy induced the highest microstructural texture from all scanning strategies used. The monotonic tensile test results highlighted that the material exhibits significant anisotropic properties, depending on both the specimen orientation and the scanning strategy. Regardless of the scanning strategy used, the lowest mechanical performances of IN 625, in terms of strength values, were recorded for specimens built in the vertical position, as compared with all the other orientations.

scholarly journals The Effect of a Scanning Strategy on the Residual Stress of 316L Steel Parts Fabricated by Selective Laser Melting (SLM)

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1821 ◽  
Author(s):  
Di Wang ◽  
Shibiao Wu ◽  
Yongqiang Yang ◽  
Wenhao Dou ◽  
Shishi Deng ◽  
...  
Keyword(s):  
Residual Stress ◽  
Selective Laser Melting ◽  
Laser Scanning ◽  
Effective Means ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Deformation Degree ◽  
316L Steel ◽  
Stress And Deformation ◽  
Scanning Strategies

The laser scanning strategy has an important influence on the surface quality, residual stress, and deformation of the molten metal (deformation behavior). A divisional scanning strategy is an effective means used to reduce the internal stress of the selective laser melting (SLM) metal part. In order to understand and optimize the divisional scanning strategy, three divisional scanning strategies and an S-shaped orthogonal scanning strategy are used to produce 316L steel parts in this study. The influence of scanning strategy on the produced parts is verified from the aspects of densification, residual stress distribution and deformation. Experiments show that the 316L steel alloy parts adopted spiral divisional scanning strategy can not only obtain the densification of 99.37%, but they also effectively improve the distribution of residual stress and control the deformation degree of the produced parts. Among them, the spiral divisional scanning sample has the smallest residual stress in plane direction, and its σx and σy stress are controlled within 204 MPa and 103 MPa. The above results show that the spiral divisional scanning is the most conducive strategy to obtain higher residual stress performance of SLM 316L steel parts.

Analytical Solution of Temperature Distribution in a Nonuniform Medium Due to a Moving Laser Beam and a Double Beam Scanning Strategy in the Selective Laser Melting Process

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Loong-Ee Loh ◽  
Jie Song ◽  
Fenglin Guo ◽  
Guijun Bi
Keyword(s):  
Temperature Distribution ◽  
Analytical Solution ◽  
Laser Beam ◽  
Selective Laser Melting ◽  
Melting Process ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Beam Scanning ◽  
Double Beam ◽  
Scanning Strategies

Selective laser melting (SLM) has received increasing attention in recent years as an innovative manufacturing technique. The present SLM process only uses a single laser beam to melt and consolidate the powder, which may result in excessive evaporation. In this paper, a double beam scanning strategy is investigated in which the first laser beam preheats the powder just below the sintering point while the second laser beam completely melts the powder. An analytical solution on the temperature distribution heated by a moving laser beam in the powder-bulk domain is derived and is used to determine the critical radius of the first laser beam. The single and double beam scanning strategies are compared numerically and it is found that double beam scanning can effectively reduce material evaporation and increase the amount of powder melted in the SLM process.

scholarly journals Edge and corner effects in selective laser melting of IN 625 alloy

2020 ◽  
Vol 7 ◽  
pp. 8 ◽  
Author(s):  
Gheorghe Matache ◽  
Mihai Vladut ◽  
Alexandru Paraschiv ◽  
Raluca Mihaela Condruz
Keyword(s):  
Selective Laser Melting ◽  
Laser Power ◽  
Scanning Speed ◽  
Experimental Investigations ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Melt Pool ◽  
Corner Effects ◽  
Different Levels ◽  
Surface Changes

Experimental investigations on top surface of prismatic specimens, manufactured by Selective Laser Melting of IN 625 alloy, were carried out in order to assess the influence of laser power and scanning speed on edge and corner effects. Since the melt-pool behaviour is strongly influenced by the process parameters, all specimens were manufactured with no contour using the same layer thickness, hatch distance and scanning strategy at different levels of laser powers and scanning speeds. 3D laser surface scanning was performed in order to measure surface changes. The experimental results have revealed that melt-pool behaviour during solidification generates elevated ridges on both specimen sides and corners that are strongly influenced by the energy input. The edge ridges width increases with increasing the laser power and decrease with increasing the scanning speed, the rising of corners being much more pronounced. On the contrary, at constant laser power and variable scanning speeds the edge and corner ridges decrease.

scholarly journals Effect of Shielding Gas Volume Flow on the Consistency of Microstructure and Tensile Properties of 316L Manufactured by Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 205
Author(s):  
Ruochen Ding ◽  
Jun Yao ◽  
Baorui Du ◽  
Kailun Li ◽  
Tao Li ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Selective Laser Melting ◽  
Mass Production ◽  
Strong Influence ◽  
Base Plate ◽  
Volume Flow ◽  
Shielding Gas ◽  
Laser Melting ◽  
Gas Volume ◽  
By Products

In recent years, selective laser melting (SLM) has been widely used in aerospace, automobile, biomedicine and other fields. However, there still remain many challenges to obtain consistent parts at the different positions on the base plate, which could be harmful to the industrial mass-production. In SLM process, the process by-products that flow with the shielding gas may influence the microstructure and tensile properties of the parts placed on different positions of the base plate. In this study, the velocity field of the shielding gas with different shielding gas volume flows was simulated. The tensile properties of the samples fabricated with different shielding gas volume flow were experimentally studied. The results show that the shielding gas volume flow has a strong influence on the sample consistency, and proper increase in shielding gas volume flows can be beneficial to consistency and tensile strength.

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