scholarly journals Effect of the Solution Temperature on the Precipitates and Grain Evolution of IN718 Fabricated by Laser Additive Manufacturing

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 340 ◽  
Author(s):  
Yu Cao ◽  
Pucun Bai ◽  
Fei Liu ◽  
Xiaohu Hou ◽  
Yuhao Guo
Keyword(s):  
Selective Laser Melting ◽  
Treatment Temperature ◽  
Solution Temperature ◽  
Recrystallization Process ◽  
Laser Melting ◽  
Laser Additive Manufacturing ◽  
Laves Phases ◽  
The Matrix ◽  
In718 Superalloy ◽  
Recrystallized Grain Size

The effects of the solution heat treatment temperature on the precipitates, grain boundary evolution and response of the microhardness of Inconel 718 (IN718) superalloy fabricated by selective laser melting (SLM) were investigated. It was found that: (1) The long-chained Laves phases formed in the as-deposited condition dissolved into the matrix when the solution temperature rises above 980 °C. (2) The width-to-length ratio was maintained at approximately 1.6 when the solution was heated from 980 °C to 1080 °C, and dropped down to 1.03 when heated to 1130 °C. (3) Low-angle grain boundaries kept the same number fraction of 65% from 980 to 1080 °C as the as-deposited condition, and decreased dramatically from 1090 to 1130 °C to 4%. (4) Annealing twin boundaries occurred at 1090 °C with a number fraction of 3%, and quickly increased to 65% when heated to 1130 °C. It is concluded that the static recrystallization of IN718 fabricated by selective laser melting (SLM) occurred at 1090 °C and fast proceeded to full recrystallization at 1130 °C. The forming of annealing twins accompanies the recrystallization process and is an effective way to refine the recrystallized grain size.

Properties of aluminum metal matrix composites manufactured by selective laser melting

2021 ◽  
Vol 112 (7) ◽  
pp. 552-564
Author(s):  
Christian Felber ◽  
Florian Rödl ◽  
Ferdinand Haider
Keyword(s):  
Additive Manufacturing ◽  
Aluminum Alloys ◽  
Selective Laser Melting ◽  
Metal Matrix ◽  
High Hardness ◽  
High Strength ◽  
Laser Melting ◽  
Scanning Calorimetry ◽  
Particle Reinforcement ◽  
The Matrix

Abstract The most promising metal processing additive manufacturing technique in industry is selective laser melting, but only a few alloys are commercially available, limiting the potential of this technique. In particular high strength aluminum alloys, which are of great importance in the automotive industry, are missing. An aluminum 2024 alloy, reinforced by Ti-6Al-4V and B4C particles, could be used as a high strength alternative for aluminum alloys. Heat treating can be used to improve the mechanical properties of the metal matrix composite. Dynamic scanning calorimetry shows the formation of Al2Cu precipitates in the matrix instead of the expected Al2CuMg phases due to the loss of magnesium during printing, and precipitation processes are accelerated due to particle reinforcement and additive manufacturing. Strong reactions between aluminum and Ti-6Al-4V are observed in the microstructure, while B4C shows no reaction with the matrix or the titanium. The material shows high hardness, high stiffness, and low ductility through precipitation and particle reinforcement.

Review on Powder-Bed Laser Additive Manufacturing of Inconel 718 Parts

2015 ◽  
Author(s):  
Xiaoqing Wang ◽  
Xibing Gong ◽  
Kevin Chou
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Literature Review ◽  
Selective Laser Melting ◽  
Inconel 718 ◽  
Manufacturing Processes ◽  
Laser Melting ◽  
Laser Additive Manufacturing ◽  
Powder Bed ◽  
General Aspects

This study presents a thorough literature review on the powder-bed laser additive manufacturing processes such as selective laser melting (SLM) of Inconel 718 parts. The paper first introduces the general aspects of powder-bed laser additive manufacturing and then discusses the unique characteristics and advantages of SLM. Moreover, the bulk of this study includes extensive discussions of microstructures and mechanical properties, together with the application ranges, of Inconel 718 parts fabricated by SLM.

scholarly journals Microstructure and Mechanical Properties of Carbides Reinforced Nickel Matrix Alloy Prepared by Selective Laser Melting

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4792
Author(s):  
Tian Xia ◽  
Rui Wang ◽  
Zhongnan Bi ◽  
Rui Wang ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Selective Laser Melting ◽  
High Efficiency ◽  
Matrix Alloy ◽  
Tensile Tests ◽  
Laser Melting ◽  
Haynes 230 ◽  
Transmission Electron ◽  
Room Temperature Yield Strength ◽  
The Matrix

Selective laser melting was used to prepare the ceramic particles reinforced nickel alloy owing to its high designability, high working flexibility and high efficiency. In this paper, a carbides particles reinforced Haynes 230 alloy was prepared using SLM technology to further strengthen the alloy. Microstructures of the carbide particles reinforced Haynes 230 alloy were investigated using electron microscopy (SEM), electron probe microanalysis (EPMA) and transmission electron microscopy (TEM). Meanwhile, the tensile tests were carried out to determine the strengths of the composite. The results show that the microstructure of the composite consisted of uniformly distributed M23C6 and M6C type carbides and the strengths of the alloy were higher than the matrix alloy Haynes 230. The increased strengths of the carbide reinforced Haynes 230 alloy (room temperature yield strength 113 MPa increased, ~ 33.2%) can be attributed to the synergy strengthening including refined grain strengthening, Orowan strengthening and dislocation strengthening.

scholarly journals Power Density Distribution for Laser Additive Manufacturing (SLM): Potential, Fundamentals and Advanced Applications

Technologies ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 5 ◽  
Author(s):  
Alexander Metel ◽  
Michael Stebulyanin ◽  
Sergey Fedorov ◽  
Anna Okunkova
Keyword(s):  
Additive Manufacturing ◽  
Laser Beam ◽  
Density Distribution ◽  
Power Density ◽  
Selective Laser Melting ◽  
Laser Melting ◽  
Laser Additive Manufacturing ◽  
Power Density Distribution ◽  
Advanced Applications

Problems with the laser additive manufacturing of metal parts related to its low efficiency are known to hamper its development and application. The method of selective laser melting of metallic powders can be improved by the installation of an additional laser beam modulator. This allows one to control the power density distribution optically in the laser beam, which can influence the character of heat and mass transfer in a molten pool during processing. The modulator contributes alternative modes of laser beam: Gaussian, flat top (top hat), and donut (bagel). The study of its influence includes a mathematical description and theoretical characterization of the modes, high-speed video monitoring and optical diagnostics, characterization of processing and the physical phenomena of selective laser melting, geometric characterization of single tracks, optical microscopy, and a discussion of the obtained dependences of the main selective laser melting (SLM) parameters and the field of its optimization. The single tracks were produced using the advanced technique of porosity lowering. The parameters of the obtained samples are presented in the form of 3D graphs. The further outlook and advanced applications are discussed.

scholarly journals Investigation of the Effects of an Intense Pulsed Ion Beam on the Surface Melting of IN718 Superalloy Prepared with Selective Laser Melting

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1178
Author(s):  
Min Min ◽  
Shuiting Ding ◽  
Xiao Yu ◽  
Shijian Zhang ◽  
Haowen Zhong ◽  
...  
Keyword(s):  
Energy Density ◽  
Selective Laser Melting ◽  
Ion Beam ◽  
Pulse Length ◽  
High Energy ◽  
Surface Melting ◽  
High Energy Density ◽  
Irradiation Effect ◽  
Laser Melting ◽  
In718 Superalloy

Intense pulsed ion beam irradiation on IN718 superalloy prepared with selective laser melting as an after-treatment for surface melting is introduced. It is demonstrated that intense pulsed ion beam composed of protons and carbon ions, with a maximum current density of 200 A/cm2 and a pulse length of 80 ns, can induce surface melting and the surface roughness changes significantly due to the generation of micro-defects and the flow of the molten surface. Irradiation experiments and thermal field simulation revealed that the energy density of the ion beam plays a predominant role in the irradiation effect—with low energy density, the flow of molten surface is too weak to smooth the fluctuations on the surface. With high energy density, the surface can be effectively melted and smoothened while micro-defects, such as craters, may be generated and can be flattened by an increased number of pulses. The research verified that for the surface melting with intense pulsed ion beam (IPIB), higher energy density should be used for stronger surface fluidity and a greater pulse number is also required for the curing of surface micro-defects.

scholarly journals The Heat Treatment Influence on the Microstructure and Hardness of TC4 Titanium Alloy Manufactured via Selective Laser Melting

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1318 ◽  
Author(s):  
Zhan-Yong Zhao ◽  
Liang Li ◽  
Pei-Kang Bai ◽  
Yang Jin ◽  
Li-Yun Wu ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Titanium Alloy ◽  
Critical Temperature ◽  
Selective Laser Melting ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Laser Melting ◽  
Β Phase ◽  
Α Phase ◽  
Increasing Temperature

In this research, the effect of several heat treatments on the microstructure and microhardness of TC4 (Ti6Al4V) titanium alloy processed by selective laser melting (SLM) is studied. The results showed that the original acicular martensite α′-phase in the TC4 alloy formed by SLM is converted into a lamellar mixture of α + β for heat treatment temperatures below the critical temperature (T0 at approximately 893 °C). With the increase of heat treatment temperature, the size of the lamellar mixture structure inside of the TC4 part gradually grows. When the heat treatment temperature is above T0, because the cooling rate is relatively steep, the β-phase recrystallization transforms into a compact secondary α-phase, and a basketweave structure can be found because the primary α-phase develop and connect or cross each other with different orientations. The residence time for TC4 SLM parts when the treatment temperature is below the critical temperature has little influence: both the α-phase and the β-phase will tend to coarsen but hinder each other, thereby limiting grain growth. The microhardness gradually decreases with increasing temperature when the TC4 SLM part is treated below the critical temperature. Conversely, the microhardness increases significantly with increasing temperature when the TC4 SLM part is treated above the critical temperature.

scholarly journals Effect of the Distance from Build Platform and Post-Heat Treatment of AlSi10Mg Alloy Manufactured by Single- and Multi-Laser Selective Laser Melting

2021 ◽  
Author(s):  
Emanuela Cerri ◽  
Emanuele Ghio ◽  
Giovanni Bolelli
Keyword(s):  
Heat Treatment ◽  
Selective Laser Melting ◽  
Vickers Microhardness ◽  
Treatment Temperature ◽  
Progressive Decrease ◽  
Laser Melting ◽  
Post Heat Treatment ◽  
Working Temperature ◽  
Eutectic Si ◽  
Higher Temperature

AbstractIn the present study, AlSi10Mg samples produced by selective laser melting (SLM) were studied. Samples were machined from two types of bars obtained through different methods: either single laser (SL) or multiple laser (ML) machine setup. The bars were built perpendicular to the platform, which was pre-heated at 150 °C (working temperature), up to a height of 300 mm. The effect of the distance from the platform on the mechanical properties was investigated through tensile samples in as-built condition and after unconventional heat treatments (U-HT). Tensile strength changed by 80 MPa along the Z-axis (build direction) for SL case and by 100 MPa for ML case in the as-built samples. Vickers microhardness revealed an analogous gradient. This was correlated to a gradient in intra-granular precipitates' distribution along the Z-axis, as revealed by scanning electron microscopy (SEM). An unconventional heat treatment at 175 °C for 6h slightly improves the mechanical strength; higher temperature treatments at 200 and 225 °C for the same duration cause a progressive decrease in strength with an increase in elongation. The amount and size of the precipitates and the thickness of eutectic Si change with the heat treatment temperature, justifying the mechanical behavior.

scholarly journals Effect of Layer Thickness in Selective Laser Melting on Microstructure of Al/5 wt.%Fe2O3Powder Consolidated Parts

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Sasan Dadbakhsh ◽  
Liang Hao
Keyword(s):  
Layer Thickness ◽  
Selective Laser Melting ◽  
Laser Power ◽  
Fine Particles ◽  
Lower Layer ◽  
Scanning Speed ◽  
Laser Melting ◽  
The Matrix ◽  
Fe Intermetallics

In situreaction was activated in the powder mixture of Al/5 wt.%Fe2O3by using selective laser melting (SLM) to directly fabricate aluminium metal matrix composite parts. The microstructural characteristics of thesein situconsolidated parts through SLM were investigated under the influence of thick powder bed, 75 μm layer thickness, and 50 μm layer thickness in various laser powers and scanning speeds. It was found that the layer thickness has a strong influence on microstructural outcome, mainly attributed to its impact on oxygen content of the matrix. Various microstructural features (such as granular, coralline-like, and particulate appearance) were observed depending on the layer thickness, laser power, and scanning speed. This was associated with various material combinations such as pure Al, Al-Fe intermetallics, and Al(-Fe) oxide phases formed afterin situreaction and laser rapid solidification. Uniformly distributed very fine particles could be consolidated in net-shape Al composite parts by using lower layer thickness, higher laser power, and lower scanning speed. The findings contribute to the new development of advanced net-shape manufacture of Al composites by combining SLM andin situreaction process.

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