Accelerated Corrosion Analysis of AlSi10Mg Alloy Manufactured by Selective Laser Melting (SLM)

2018 ◽  
Vol 69 (4) ◽  
pp. 975-981 ◽  
Author(s):  
Camil Lancea ◽  
Lucia Antoneta Chicos ◽  
Sebastian Marian Zaharia ◽  
Mihai Alin Pop ◽  
Augustin Semenescu ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
High Salinity ◽  
Metal Powders ◽  
High Power Laser ◽  
Optical Analysis ◽  
Laser Melting ◽  
Power Laser ◽  
Accelerated Corrosion ◽  
3D Geometry ◽  
Complex Parts

The Selective Laser Melting (SLM) technology uses metal powders as building material which is melted and welded together using a high-power laser in order to obtain quick configuration of complex parts, most often for testing them. Another advantage of this method is the fact that allows obtaining any 3D geometry of the parts, even parts that cannot be processed through conventional manufacturing procedures. In this work were performed a number of tests for accelerated corrosion of AlSi10Mg alloy specimens in order to determine their mean life in the conditions of their use in a high salinity environment. For specimens, optical analysis was used the SEM microscope which has the advantage of obtaining an enlarged image of the investigated objects without processing. Following these analyses, it has been determined the mass loss of specimens due to corrosion.

scholarly journals Selective Laser Melting of Biomaterial (Pure Titanium) with High-Power Laser

2012 ◽  
Vol 33 (2) ◽  
pp. 166-174 ◽  
Author(s):  
Takayuki Nakamoto ◽  
Nobuhiko Shirakawa ◽  
Naruaki Shinomiya ◽  
Haruyuki Inui
Keyword(s):  
Selective Laser Melting ◽  
High Power ◽  
Pure Titanium ◽  
High Power Laser ◽  
Laser Melting ◽  
Power Laser

scholarly journals Thermodynamic Behavior of Fe-Mn and Fe-Mn-Ag Powder Mixtures during Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 234
Author(s):  
Jakob Kraner ◽  
Jožef Medved ◽  
Matjaž Godec ◽  
Irena Paulin
Keyword(s):  
Selective Laser Melting ◽  
Manganese Oxides ◽  
Elevated Temperatures ◽  
Manganese Content ◽  
Chemical Compositions ◽  
Metal Powders ◽  
Laser Melting ◽  
Powder Mixtures ◽  
Ε Martensite ◽  
The Impact

Additive manufacturing is a form of powder metallurgy, which means the properties of the initial metal powders (chemical composition, powder morphology and size) impact the final properties of the resulting parts. A complete characterization, including thermodynamic effects and the behavior of the metal powders at elevated temperatures, is crucial when planning the manufacturing process. The analysis of the Fe-Mn and Fe-Mn-Ag powder mixtures, made from pure elemental powders, shows a high susceptibility to sintering in the temperature interval from 700 to 1000 °C. Here, numerous changes to the manganese oxides and the αMn to βMn transformation occurred. The problems of mechanically mixed powders, when using selective laser melting, were highlighted by the low flowability, which led to a less controllable process, an uncontrolled arrangement of the powder and a large percentage of burnt manganese. All this was determined from the altered chemical compositions of the produced parts. The impact of the increased manganese content on the decreased probability of the transformation from γ-austenite to ε-martensite was confirmed. The ε-martensite in the microstructure increased the hardness of the material, but at the same time, its magnetic properties reduce the usefulness for medical applications. However, the produced parts had comparable elongations to human bone.

Influence of Abrasive Materials in Fluidised Bed Machining of AlSi10Mg Parts Made through Selective Laser Melting Technology

2019 ◽  
Vol 813 ◽  
pp. 129-134 ◽  
Author(s):  
Andrea El Hassanin ◽  
Maurizio Troiano ◽  
Alessia Teresa Silvestri ◽  
Vincenzo Contaldi ◽  
Fabio Scherillo ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Selective Laser Melting ◽  
Impact Angle ◽  
Fluidised Bed ◽  
Laser Melting ◽  
Abrasive Material ◽  
Melting Technology ◽  
Post Process ◽  
The Impact ◽  
Complex Parts

Metal Additive Manufacturing technologies development is increasing in a remarkable way due to their great potential concerning the production of complex parts with tailored characteristics in terms of design, material properties, usage and applications. Among all, the most widespread technologies are the Powder Bed Fusion based technologies such as Selective Laser Melting and Electron Beam Melting. However, the high surface roughness of the as-built parts still represents one of the major limitations, making necessary the adoption of post-process finishing to match the technological requirements for most of the fields of application. In this scenario, Fluidised Bed Machining represents an emerging finishing technology that could overcome some of the limitations of the most common methods, especially in terms of feasibility for the treatment of complex parts thanks to the fluid-like mobility of the abrasive material. This work deals with the preliminary tests of the Fluidised Bed Machining of additive manufactured samples using alumina as the abrasive material, investigating the effects of a high abrasive/substrate hardness ratio condition. The experiments were carried out on small plates of AlSi10Mg alloy made through Selective Laser Melting technology, built in the vertical direction with respect to the building plate. The influence of the impact angle and treatment time were investigated under bubbling fluidization conditions. Surface morphology evaluations were carried out pre and post process by means of Confocal Microscopy and Scanning Electron Microscopy (SEM). Weight loss measurements were conducted to evaluate the material removal rates as well. Results show a small influence of the specific impact angle, a slight reduction of the surface roughness and an asymmetrical effect of treatment, acting mostly on the sintered powders forming the peaks of the as-built surface.

Modeling, Simulation and Experimental Validation of Heat Transfer During Selective Laser Melting

2015 ◽  
Author(s):  
Mohammad Masoomi ◽  
Xiang Gao ◽  
Scott M. Thompson ◽  
Nima Shamsaei ◽  
Linkan Bian ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Heat Fluxes ◽  
Transient Temperature ◽  
Thermal Gradients ◽  
Layer By Layer ◽  
Metal Powders ◽  
Laser Melting ◽  
Powder Bed

Selective Laser Melting (SLM), a laser powder-bed fusion (PBF-L) additive manufacturing method, utilizes a laser to selectively fuse adjacent metal powders. The powders are aligned in a bed that moves vertically to allow for layer-by-layer part construction-Process-related heat transfer and thermal gradients have a strong influence on the microstructural features, and subsequent mechanical properties, of the parts fabricated via SLM. In order to understand and control the heat transfer inherent to SLM, and to ensure high quality parts with targeted microstructures and mechanical properties, comprehensive knowledge of the related energy and mass transport during manufacturing is required. In this study, the transient temperature distribution within and around parts being fabricated via SLM is numerically simulated and the results are provided to aid in quantify the SLM heat transfer. In order to verify simulation output, and to estimate actual thermal gradients and heat transfer, experiments were separately conducted within a SLM machine using a substrate with embedded thermocouples. The experiments focused on characterizing heat fluxes during initial deposition on an initially-cold substrate and during the fabrication of a thin-walled structure built via stainless steel 17-4 powders. Results indicate that it is important to model heat transfer thorough powder bed as well as substrate.

Optical Monitoring and Numerical Simulation of Temperature Distribution at Selective Laser Melting of Ti6Al4V Alloy

2015 ◽  
Vol 828-829 ◽  
pp. 474-481 ◽  
Author(s):  
Ivan Zhirnov ◽  
Ina Yadroitsava ◽  
Igor Yadroitsev
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Selective Laser Melting ◽  
Ti6al4v Alloy ◽  
Advanced Technology ◽  
Temperature Fields ◽  
Optical Monitoring ◽  
Metal Powders ◽  
Laser Melting ◽  
Ir Camera

Selective laser melting (SLM) is a modern method for producing objects with complex shape and fine structures in one working cycle from metal powders. Combination of the advanced technology of SLM with unique properties of Ti6Al4V alloy allows creating complex 3D objects for medicine or aerospace industry. Since properties of SLM parts depend on the geometrical characteristics of tracks and their cohesion, optical monitoring is actually used to for control the process. Temperature gradient determines the microstructure and mechanical properties of the SLM part, so studies about temperature fields are primarily important. On-line monitoring during laser scanning of Ti6Al4V alloy and formation of a single track in real-time with high-speed IR camera was studied. Numerical simulation allowed estimation the temperature distribution during processing. Conclusion regarding control system based on the online monitoring of deviations of the signal from IR camera during the SLM process was done.

Investigation of Sectoral Scanning in Selective Laser Melting

2010 ◽  
Author(s):  
Evren Yasa ◽  
Jan Deckers ◽  
Jean-Pierre Kruth ◽  
Marleen Rombouts ◽  
Jan Luyten
Keyword(s):  
Mechanical Properties ◽  
Residual Stresses ◽  
Laser Beam ◽  
Surface Quality ◽  
Selective Laser Melting ◽  
Random Order ◽  
Laser Source ◽  
Metal Powders ◽  
Laser Melting ◽  
Powder Bed

Selective laser melting (SLM), a powder metallurgical (PM) additive manufacturing (AM) technology, is able to produce fully functional parts directly from standard metal powders without using any intermediate binders or any additional post-processing steps. During the process, a laser beam selectively scans a powder bed according to the CAD data of the part to be produced and completely melts the powder particles together. Stacking and bonding two-dimensional powder layers in this way, allows production of fully dense parts with any geometrical complexity. The scanning of the powder bed by the laser beam can be achieved in several different ways, one of which is island or sectoral scanning. In this way, the area to be scanned is divided in small square areas (‘sectors’) which are scanned in a random order. This study is carried out to explore the influence of sectoral scanning on density, surface quality, mechanical properties and residual stresses formed during SLM. The experiments are carried out on a machine with an Nd:YAG laser source using AISI 316L stainless steel powder. As a result of this experimental study, it is concluded that sectoral scanning has some advantages such as lower residual stresses and better surface quality. However, the selection of parameters related to sectoral scanning is a critical task since it may cause aligned porosity at the edges between sectors or scanned tracks, which is very undesired in terms of mechanical properties.

Factors of strength increasing of metals produced by selective laser melting of powders

2019 ◽  
pp. 68-75 ◽  
Author(s):  
B. K. Barakhtin ◽  
A. S. Zhukov ◽  
V. V. Bobyr ◽  
I. V. Shakirov ◽  
P. A. Kuznetsov
Keyword(s):  
Chemical Composition ◽  
Selective Laser Melting ◽  
Mechanical Tests ◽  
Strength Characteristics ◽  
Strength Increase ◽  
Metal Powders ◽  
Laser Melting ◽  
Standard Samples ◽  
Ultrafine Grained ◽  
Identical Chemical Composition

Standard samples of metal powders of various chemical composition were made for mechanical tests by selective laser melting. The paper describes an increase in strength characteristics of all samples made by melting comparing with similar parameters of monolithic samples of identical chemical composition. It is established that ultrafine-grained structure and condensation of nanoparticles could be cosidered factors of strength increase.

Progress on Investigation of Pores During Selective Laser Melting of Metal Powders and Future Work Discussion

2011 ◽  
Vol 291-294 ◽  
pp. 3088-3094
Author(s):  
Jin Hui Liu ◽  
Wen Juan Xie ◽  
Qing Song Wei ◽  
Li Wang
Keyword(s):  
Selective Laser Melting ◽  
Physical And Mechanical Properties ◽  
Porous Metal ◽  
Complex Structures ◽  
Metal Powders ◽  
Porous Metals ◽  
Laser Melting ◽  
Metal Structures ◽  
Metal Parts ◽  
Future Work

Pores are always considered as a kind of defect during manufacturing metal parts via many conventional processes. But porous metals have outstanding physical and mechanical properties which providing them double natures of function and structure, and are applied in many fields of science and technology. Selective laser melting (SLM), developed within current years, has the advantages of producing metal parts with complex structures, and can be used to manufacture complex structures of any kind theoretically. A new method of making porous complicated metal structures via SLM is put forward. Then, the meaning of this method, research advance and future work discussion are presented in this paper, which lays a method foundation for future study and build a new field for both porous metal parts and SLM technology.

scholarly journals Beam Diameter Dependence of Performance in Thick-Layer and High-Power Selective Laser Melting of Ti-6Al-4V

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1237 ◽  
Author(s):  
Wentian Shi ◽  
Yude Liu ◽  
Xuezhi Shi ◽  
Yanjun Hou ◽  
Peng Wang ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
High Power ◽  
Large Diameter ◽  
Thick Layer ◽  
Beam Diameter ◽  
Laser Melting ◽  
Power Laser ◽  
Beam Laser ◽  
Melt Pool ◽  
Thick Layers

A 400 W high-power laser was used to fabricate 200-µm-thick Ti-6Al-4V samples to evaluate the effects of small (50 μm) and large (200 μm) beam diameter on density, microstructure and mechanical properties. A series of single-track experiments demonstrated that it was challenging for the small-beam laser to fabricate smooth and defect-free scan tracks. A larger beam diameter efficiently avoided process instability and provided a more stable and uniform melt pool. By increasing the beam diameter, the density of multilayer samples reached 99.95% of the theoretical value, which is much higher than that achieved with the small beam diameter. However, it was difficult to completely eliminate defects due to serious spatter and evaporation. Moreover, all of the generated samples had relatively coarse surfaces. For the large beam diameter of 200 µm, the optimal yield strength, ultimate tensile strength and elongation were 1150 MPa, 1200 MPa and 8.02%, respectively. In comparison, the small beam diameter of 50 µm resulted in values of 1035 MPa, 1100 MPa and 5.91%, respectively. Overall, the large-diameter laser is more suitable for high-power selective laser melting (SLM) technology, especially for thick layers.

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