scholarly journals Effect of Scanning Strategy During Selective Laser Melting on Surface Topography, Porosity, and Microstructure of Additively Manufactured Ti-6Al-4V

2019 ◽  
Vol 9 (24) ◽  
pp. 5554 ◽  
Author(s):  
Emilie Hørdum Valente ◽  
Carsten Gundlach ◽  
Thomas L. Christiansen ◽  
Marcel A. J. Somers
Keyword(s):  
Selective Laser Melting ◽  
Surface Texture ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Total Porosity ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Bottom Part ◽  
Line Scan ◽  
Surface Measurements

The effect of the scanning strategy during selective laser melting (SLM) of Ti-6Al-4V was investigated. An optimized cellular scan strategy (island scan modeled) was compared to a simple cellular scan strategy (island scan stripes) and a simple antiparallel line scanning strategy (line scan). Surface texture was investigated by optical three-dimensional (3D) surface measurements, which when combined with light optical microscopy (LOM), revealed deflections caused by the thermal stresses during the build process. Elevated edges caused by the edge-effect dominate the surface texture of all investigated specimens. The scanning strategy determines the surface texture, and the lowest surface roughness was obtained by the line scan strategy. Porosity was investigated with X-ray computed tomography-imaging. Mainly spherical porosity was observed for the line scan and island scan modeled specimens, while the island scan stripes strategy showed more lack-of-fusion defects and a higher total porosity amount. Microstructure was investigated with LOM and scanning electron microscopy (SEM). The microstructure in Ti-6Al-4V was largely martensitic α’ and prior β grains. The morphology is different for the various scan strategies, and decomposition of α’ into lamellar α/β was observed in the bottom part of the island scan specimen. Accordingly, the hardness decreased in the decomposed part of the specimen.

Fabrication of three-dimensional connected W-Cu10Sn composites by selective laser melting

2020 ◽  
Vol 264 ◽  
pp. 127377 ◽  
Author(s):  
Zhenlu Zhou ◽  
Zhen Tan ◽  
Dingyong He ◽  
Zheng Zhou ◽  
Li Cui ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Three Dimensional ◽  
Laser Melting

Development of 3D Finite Element Model for Predicting Process-Induced Defects in Additive Manufacturing by Selective Laser Melting (SLM)

2016 ◽  
Author(s):  
Bilal Hussain ◽  
A. Sherif El-Gizawy
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
Selective Laser Melting ◽  
Thermal Stresses ◽  
Cost Effective ◽  
Element Model ◽  
Laser Melting ◽  
Two Phase ◽  
Free Process ◽  
Manufacturing Techniques

Selective Laser Melting (SLM) is one of the important Additive Manufacturing techniques for building functional products. Nevertheless, the absence of accurate models for predicting the SLM process behavior, delays development of cost effective and defects free process. This work presents a coupled thermo-mechanical numerical model to capture the two phase (solid-liquid) solidification melting phenomena that occur in the process. The proposed model will also predict the evolvement of process-induced properties and defects particularly residual stresses caused by temperature gradient and thermal stresses. CO2 or Nd:YAG laser beam can be used as a heat source with a Gaussian distribution for the laser beam energy.

Selective Laser Melting of Ti42Nb Composite Powder and the Effect of Laser Re-Melting

2019 ◽  
Vol 801 ◽  
pp. 270-275 ◽  
Author(s):  
Sheng Huang ◽  
Swee Leong Sing ◽  
Wai Yee Yeong
Keyword(s):  
Selective Laser Melting ◽  
Composite Powder ◽  
Stress Shielding ◽  
Alloyed Powder ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Implant Materials ◽  
Bio Compatibility ◽  
Alloy Systems

Ti-Nb based alloys have the potential to be used as structural implant materials due to their excellent bio-compatibility and ability to reduce stress shielding. The idea to additively manufacture Ti-Nb based alloys using selective laser melting (SLM) technology can further improve the resultant implant quality. However, the lack of economically sound and readily available pre-alloyed powder has pushed for the usage of composite powder as a means to hasten research pace in fabricating new alloy systems via SLM. The usage of Ti-Nb composite powder can lead to several problems, particularly the issue of macro-segregation. Hence, this paper presents the potential of laser re-melting scanning strategy to address macro-segregation without sacrificing (or even improving) density of parts fabricated by SLM.

scholarly journals Fabrication Of Scaffolds From Ti6Al4V Powders Using The Computer Aided Laser Method

2015 ◽  
Vol 60 (2) ◽  
pp. 1065-1070 ◽  
Author(s):  
L.A. Dobrzański ◽  
A.D. Dobrzańska-Danikiewicz ◽  
P. Malara ◽  
T.G. Gaweł ◽  
L.B. Dobrzański ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
3D Model ◽  
Three Dimensional ◽  
Plaster Cast ◽  
Laser Melting ◽  
Laser Method ◽  
Porous Implant ◽  
Unit Cells ◽  
Dimensional Shape ◽  
3D Solid

AbstractThe aim of the research, the results of which are presented in the paper, is to fabricate, by Selective Laser Melting (SLM), a metallic scaffold with Ti6Al4V powder based on a virtual model corresponding to the actual loss of a patient’s craniofacial bone. A plaster cast was made for a patient with a palate recess, and the cast was then scanned with a 3D scanner to create a virtual 3D model of a palate recess, according to which a 3D model of a solid implant was created using specialist software. The virtual 3D solid implant model was converted into a 3D porous implant model after designing an individual shape of the unit cell conditioning the size and three-dimensional shape of the scaffold pores by multiplication of unit cells. The data concerning a virtual 3D porous implant model was transferred into a selective laser melting (SLM) device and a metallic scaffold was produced from Ti6Al4V powder with this machine, which was subjected to surface treatment by chemical etching. An object with certain initially adopted assumptions, i.e. shape and geometric dimensions, was finally achieved, which perfectly matches the patient bone recesses. The scaffold created was subjected to micro-and spectroscopic examinations.

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.

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