Selective laser melting of Al and AlSi10Mg: parameter study and creep experiments

AbstractSelective laser melted (SLM) aluminum alloys are widely used for many technical applications. However, the application is limited to low temperatures due to their relatively poor creep resistance. The creep resistance and strength could be enhanced by oxide dispersion-strengthening. A hypothesis is that oxygen intake during selective laser melting can lead to formation of fine aluminum oxides and thus strengthen the SLMed part. To elucidate this in more detail, selective laser melted AlSi10Mg was tested in creep experiments at temperatures of 300 °C. Although, in other studies at lower temperatures, a relatively large stress exponent for creep was found, the high temperatures in this work led to a creep exponent of just 7 to 8, indicating no significant dispersion strengthening. Furthermore, for future research, it was necessary to investigate the feasibility of SLM with pure aluminum. For this purpose, a parameter study was carried out and an optimum parameter set for pure aluminum was found. Dense samples with a porosity below 0.2% were produced. Selective laser melting was carried out with a varying oxygen content in the inert-gas atmosphere to elucidate the hypothetic strengthening effects by oxygen intake. However, even at 800 ppm oxygen in the atmosphere, no effect on hardness and microstructure could be observed.

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Coarsening- and creep resistance of precipitation-strengthened Al–Mg–Zr alloys processed by selective laser melting

Acta Materialia ◽

10.1016/j.actamat.2020.02.008 ◽

2020 ◽

Vol 188 ◽

pp. 192-202 ◽

Cited By ~ 7

Author(s):

S. Griffiths ◽

J.R. Croteau ◽

M.D. Rossell ◽

R. Erni ◽

A. De Luca ◽

...

Keyword(s):

Selective Laser Melting ◽

Creep Resistance ◽

Laser Melting ◽

Zr Alloys

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Mechanical Properties of In-Situ Synthesis of Ti-Ti3Al Metal Composite Prepared by Selective Laser Melting

Metals ◽

10.3390/met9101121 ◽

2019 ◽

Vol 9 (10) ◽

pp. 1121 ◽

Cited By ~ 4

Author(s):

Li ◽

Liang ◽

Tian ◽

Yang ◽

Xie ◽

...

Keyword(s):

Mechanical Properties ◽

Wear Resistance ◽

Selective Laser Melting ◽

Melting Process ◽

In Situ Synthesis ◽

Metal Composite ◽

Dispersion Strengthening ◽

Laser Melting ◽

Compression Properties

Titanium composite strengthened by Ti3Al precipitations is considered to be one of the excellent materials that is widely used in engineering. In this work, we prepared a kind of Ti-Ti3Al metallic composite by in-situ synthesis technology during the SLM (selective laser melting) process, and analyzed its microstructure, wear resistance, microhardness, and compression properties. The results showed that the Ti-Ti3Al composite, prepared by in-situ synthesis technology based on SLM, had more homogeneous Ti3Al-enhanced phase dispersion strengthening structure. The grain size of the workpiece was about 1 μm, and that of the Ti3Al particle was about 200 nm. Granular Ti3Al was precipitated after the aluminum-containing workpiece formed, with a relatively uniform distribution. Regarding the mechanical properties, the hardness (539 HV) and the wear resistance were significantly improved when compared with the Cp-Ti workpiece. The compressive strength of the workpiece increased from 886.32 MPa to 1568 MPa, and the tensile strength of the workpiece increased from 531 MPa to 567 MPa after adding aluminum. In the future, the combination of in-situ synthesis technology and SLM technology can be used to flexibly adjust the properties of Ti-based materials.

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Comparative investigation of small punch creep resistance of Inconel 718 fabricated by selective laser melting

Materials Science and Engineering A ◽

10.1016/j.msea.2018.12.083 ◽

2019 ◽

Vol 745 ◽

pp. 31-38 ◽

Cited By ~ 12

Author(s):

L.Y. Wang ◽

Z.J. Zhou ◽

C.P. Li ◽

G.F. Chen ◽

G.P. Zhang

Keyword(s):

Selective Laser Melting ◽

Inconel 718 ◽

Creep Resistance ◽

Comparative Investigation ◽

Laser Melting ◽

Small Punch

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Parameter optimization of aluminum alloy thin structures obtained by Selective Laser Melting

MRS Advances ◽

10.1557/adv.2019.434 ◽

2019 ◽

Vol 4 (55-56) ◽

pp. 2997-3005

Author(s):

Malena Ley Bun Leal ◽

Barbara Bermudez-Reyes ◽

Patricia del Carmen Zambrano Robledo ◽

Omar Lopez-Botello

Keyword(s):

Selective Laser Melting ◽

Process Parameters ◽

Orthogonal Design ◽

Processing Parameters ◽

Future Research ◽

Laser Melting ◽

Complex Process ◽

The Relationship ◽

Fabrication Parameters

ABSTRACTSelective Laser Melting (SLM) involves numerous fabrication parameters, the interaction between those parameters determine the final characteristics of the resulting part and because of the latter, it is considered a complex process. Low-density components is one of the main issues of the SLM process, due to the incorrect selection of process parameters. These defects are undesired in high specialized applications (i.e. aerospace, aeronautic and medical industries). Therefore, the characterization of the defects (pores) found in aluminum parts manufacture by SLM and the relationship with fabrication parameters was performed. A robust orthogonal design of experiments was implemented to determine process parameters, and then parts were manufactured in SLM. Relative density of the samples was then characterized using the Archimedes principle and microscopy; the data was then statistically analyzed in order to determine the optimal process parameters. The main purpose of the present research was to establish the best processing parameters of an in-house SLM system, as well as to characterize the pore geometry in order to fully eliminate pores in a future research.

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Fabrication of Fe-based bulk metallic glass by selective laser melting: A parameter study

Materials & Design ◽

10.1016/j.matdes.2015.07.145 ◽

2015 ◽

Vol 86 ◽

pp. 703-708 ◽

Cited By ~ 126

Author(s):

Hyo Yun Jung ◽

Su Ji Choi ◽

Konda G. Prashanth ◽

Mihai Stoica ◽

Sergio Scudino ◽

...

Keyword(s):

Metallic Glass ◽

Bulk Metallic Glass ◽

Selective Laser Melting ◽

Parameter Study ◽

Laser Melting

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Advances in Selective Laser Melting of Nitinol Shape Memory Alloy Part Production

Materials ◽

10.3390/ma12050809 ◽

2019 ◽

Vol 12 (5) ◽

pp. 809 ◽

Cited By ~ 10

Author(s):

Josiah Chekotu ◽

Robert Groarke ◽

Kevin O’Toole ◽

Dermot Brabazon

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Selective Laser Melting ◽

Processing Parameters ◽

Inert Atmosphere ◽

Influential Factors ◽

Future Research ◽

Laser Melting ◽

High Quality ◽

Thermal Cooling

Nitinol (nickel-titanium or Ni-Ti) is the most utilized shape memory alloy due to its good superelasticity, shape memory effect, low stiffness, damping, biocompatibility, and corrosion resistance. Various material characteristics, such as sensitivity to composition and production thermal gradients, make conventional methods ineffective for the manufacture of high quality complex Nitinol components. These issues can be resolved by modern additive manufacturing (AM) methods which can produce net or near-net shape parts with highly precise and complex Nitinol structures. Compared to Laser Engineered Net Shape (LENS), Selective Laser Melting (SLM) has the benefit of more easily creating a high quality local inert atmosphere which protects chemically-reactive Nitinol powders to a higher degree. In this paper, the most recent publications related to the SLM processing of Nitinol are reviewed to identify the various influential factors involved and process-related issues. It is reported how powder quality and material composition have a significant effect on the produced microstructures and phase transformations. The effect of heat treatments after SLM fabrication on the functional and mechanical properties are noted. Optimization of several operating parameters were found to be critical in fabricating Nitinol parts of high density. The importance of processing parameters and related thermal cooling gradient which are crucial for obtaining the correct phase structure for shape memory capabilities are also presented. The paper concludes by presenting the significant findings and areas of prospective future research in relation to the SLM processing of Nitinol.

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Selective Laser Melting on Aluminum Foam Surface and Mechanical Properties of Fabricated Aluminum Foam with Nonporous Surface Layer

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.651-653.671 ◽

2015 ◽

Vol 651-653 ◽

pp. 671-676 ◽

Cited By ~ 3

Author(s):

Ryo Matsumoto ◽

Shigehiro Kanatani ◽

Hiroshi Utsunomiya

Keyword(s):

Surface Layer ◽

Selective Laser Melting ◽

Aluminum Foam ◽

Pure Aluminum ◽

Average Power ◽

Uniaxial Compression Test ◽

Surface Layers ◽

Laser Melting ◽

Plateau Stress ◽

Closed Cell

To fabricate aluminum foam having nonporous surface layer (sandwich structure), the selective laser melting (SLM) was applied to fill surface pores of a commercial closed-cell type aluminum foam with aluminum. A commercially pure aluminum powder was continuously melted and solidified by irradiating with a pulsed Nd:YAG laser with a maximum average power of 50 W. As a result, the aluminum foam having nonporous surface layer (SLM surface layer) was successfully fabricated. The compressive deformation behavior of the fabricated aluminum foam having the SLM surface layers was investigated with uniaxial compression test. The plateau stress of the aluminum foam having the SLM surface layers was improved by approximately 20%, compared with that of the aluminum foam without the SLM surface layers.

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In-Process Fabrication of Carbon-Dispersed Aluminum Matrix Composite Using Selective Laser Melting

Metals ◽

10.3390/met10050619 ◽

2020 ◽

Vol 10 (5) ◽

pp. 619 ◽

Cited By ~ 1

Author(s):

Takahiro Kimura ◽

Takayuki Nakamoto ◽

Takeshi Suyama ◽

Takao Miki

Keyword(s):

Thermal Conductivity ◽

Carbon Fiber ◽

Selective Laser Melting ◽

Laser Scanning ◽

Pure Aluminum ◽

Aluminum Matrix ◽

Copper Plate ◽

Laser Melting ◽

Mixed Powder ◽

Anisotropic Thermal Conductivity

We have investigated the basic characteristics of C/Al composites prepared in-process via selective laser melting (SLM) using a mixed powder of pure aluminum and short carbon fiber. Initially, the relationship between the relative density of the SLM composites and laser scan conditions was systematically investigated. The SLM composites were densified by applying laser scan conditions with high input energy density (>100 J/mm3). The densified SLM composite showed excellent hardness together with low thermal conductivity, due to the generation of an Al4C3 phase and increased solid-solution carbon in the α-Al matrix via the reaction between aluminum and carbon during laser irradiation. This reaction could be inhibited in SLM composites fabricated from another mixed powder of copper-plated carbon fiber and pure aluminum powder since laser absorptivity significantly decreased due to the high reflectivity of the copper plate on the carbon fiber. By investigating the Cu plated C/Al SLM composites, we demonstrated that the thermal management material having anisotropic thermal conductivity could be fabricated by controlling the carbon dispersion by using a unidirectional laser scanning pattern.

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