Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
4.7
3.4
Journals
Micromachines
Special Issues
Laser Additive Manufacturing of Metallic Materials
share announcement

Laser Additive Manufacturing of Metallic Materials

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "D：Materials and Processing".

Deadline for manuscript submissions: closed (10 October 2023) | Viewed by 25327

Special Issue Editors

Prof. Dr. Chunlei Qiu

E-Mail Website
Guest Editor
School of Materials Science and Engineering, Beihang University, Beijing 100191, China
Interests: metallic additive manufacturing; near-net-shape hot isostatic pressing; nickel-based superalloys; titanium-based alloys
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Chang-Hwan Choi

E-Mail Website
Guest Editor
Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ 07030, USA
Interests: surface modification; additive manufacturing of metals; nanofabrication; nanostructured materials; interfacial phenomena (wetting; adhesion; friction; icing; corrosion, etc.)
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Metallic additive manufacturing has gained significant interest both in industry and academia in the past decade. The small-melt-pool-based layered additive manufacturing process not only demonstrates exceptional near-net-shape manufacturing capability but also generates numerous novel metallurgical phenomena in a great number of metallic materials due to its unique processing characteristics, such as complex laser/electron beam-material interaction, steep thermal gradient within melt pools, rapid solidification, and cooling. Non-equilibrium or novel microstructure is usually produced, leading to the development of a new mechanical performance. This opens up a new window for further improvement of properties in existing metallic materials and for development and synthesis of new metallic materials with enhanced properties through alloy design and process optimization. Meanwhile, defect, stress and microstructural control have been recognized as a big challenge to the widespread industrial application of this process.

This Special Issue seeks research papers and review articles that focus on novel development of metallic additive manufacturing. The scope covers all relevant topics, including (but not limited to) laser/electron beam–material interaction; melt flow behavior; process modelling; porosity formation mechanism; cracking mechanism; novel metallurgical phenomena; new microstructural and mechanical property development; defect and microstructural control; stress development and control; novel metallic material development; new structural design and fabrication; and new applications.

Prof. Dr. Chunlei Qiu
Prof. Dr. Chang-Hwan Choi
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • metallic additive manufacturing
  • 3D printing
  • microstructural control
  • new materials development

Related Special Issue

Published Papers (10 papers)

Download All Papers
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:

Research

Jump to: Review

13 pages, 11013 KiB  
Article
Effects of Oxidized Metal Powders on Pore Defects in Powder-Fed Direct Energy Deposition
by Jong-Youn Son, Ki-Yong Lee, Seung Hwan Lee and Chang-Hwan Choi
Micromachines 2024, 15(2), 243; https://doi.org/10.3390/mi15020243 - 06 Feb 2024
Viewed by 745
Abstract
Laser-based additive manufacturing processes, particularly direct energy deposition (DED), have gained prominence for fabricating complex, functionally graded, or customized parts. DED employs a high-powered heat source to melt metallic powder or wire, enabling precise control of grain structures and the production of high-strength [...] Read more.
Laser-based additive manufacturing processes, particularly direct energy deposition (DED), have gained prominence for fabricating complex, functionally graded, or customized parts. DED employs a high-powered heat source to melt metallic powder or wire, enabling precise control of grain structures and the production of high-strength objects. However, common defects, such as a lack of fusion and pores between layers or beads, can compromise the mechanical properties of the printed components. This study focuses on investigating the recurrent causes of pore defects in the powder-fed DED process, with a specific emphasis on the influence of oxidized metal powders. This research explores the impact of intentionally oxidizing metal powders of hot work tool steel H13 by exposing them to regulated humidity and temperature conditions. Scanning electron microscopy images and energy-dispersive X-ray spectroscopy results demonstrate the clumping of powders and the deposition of iron oxides in the oxidized powders at elevated temperatures (70 °C for 72 h). Multi-layered depositions of the oxidized H13 powders on STD61 substrate do not show significant differences in cross sections among specimens, suggesting that oxidation does not visibly form large pores. However, fine pores, detected through CT scanning, are observed in depositions of oxidized powders at higher temperatures. These fine pores, typically less than 250 µm in diameter, are irregularly distributed throughout the deposition, indicating a potential degradation in mechanical properties. The findings highlight the need for careful consideration of oxidation effects in optimizing process parameters for enhanced additive manufacturing quality. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

10 pages, 5921 KiB  
Article
Enhanced Energy Absorption of Additive-Manufactured Ti-6Al-4V Parts via Hybrid Lattice Structures
by Seong Je Park, Jun Hak Lee, Jeongho Yang, Seung Ki Moon, Yong Son and Jiyong Park
Micromachines 2023, 14(11), 1982; https://doi.org/10.3390/mi14111982 - 26 Oct 2023
Cited by 2 | Viewed by 894
Abstract
In this study, we present the energy absorption capabilities achieved through the application of hybrid lattice structures, emphasizing their potential across various industrial sectors. Utilizing Ti-6Al-4V and powder bed fusion (PBF) techniques, we fabricated distinct octet truss, diamond, and diagonal lattice structures, tailoring [...] Read more.
In this study, we present the energy absorption capabilities achieved through the application of hybrid lattice structures, emphasizing their potential across various industrial sectors. Utilizing Ti-6Al-4V and powder bed fusion (PBF) techniques, we fabricated distinct octet truss, diamond, and diagonal lattice structures, tailoring each to specific densities such as 10, 30, and 50%. Furthermore, through the innovative layering of diverse lattice types, we introduced hybrid lattice structures that effectively overcome the inherent energy absorption limitations of single-lattice structures. As a result, we conducted a comprehensive comparison between single-lattice structures and hybrid lattice structures of equal density, unequivocally showcasing the latter’s superior energy absorption performance in terms of compression. The single-lattice structure, OT, showed an energy absorption of 42.6 J/m3, while the reinforced hybrid lattice structure, OT-DM, represented an energy absorption of 77.8 J/m3. These findings demonstrate the significant potential of hybrid lattice structures, particularly in energy-intensive domains such as shock absorption structures. By adeptly integrating various lattice architectures and leveraging their collective energy dissipation properties, hybrid lattice structures offer a promising avenue for addressing energy absorption challenges across diverse industrial applications. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

19 pages, 37945 KiB  
Article
Comparative Analysis of Minimum Chip Thickness, Surface Quality and Burr Formation in Micro-Milling of Wrought and Selective Laser Melted Ti64
by Uçan Karakılınç, Berkay Ergene, Bekir Yalçın, Kubilay Aslantaş and Ali Erçetin
Micromachines 2023, 14(6), 1160; https://doi.org/10.3390/mi14061160 - 30 May 2023
Cited by 11 | Viewed by 1458
Abstract
Selective laser melting (SLM) is a three-dimensional (3D) printing process that can manufacture functional parts with complex geometries as an alternative to using traditional processes, such as machining wrought metal. If precision and a high surface finish are required, particularly for creating miniature [...] Read more.
Selective laser melting (SLM) is a three-dimensional (3D) printing process that can manufacture functional parts with complex geometries as an alternative to using traditional processes, such as machining wrought metal. If precision and a high surface finish are required, particularly for creating miniature channels or geometries smaller than 1 mm, the fabricated parts can be further machined. Therefore, micro milling plays a significant role in the production of such miniscule geometries. This experimental study compares the micro machinability of Ti-6Al-4V (Ti64) parts produced via SLM compared with wrought Ti64. The aim is to investigate the effect of micro milling parameters on the resulting cutting forces (Fx, Fy, and Fz), surface roughness (Ra and Rz), and burr width. In the study, a wide range of feed rates was considered to determine the minimum chip thickness. Additionally, the effects of the depth of cut and spindle speed were observed by taking into account four different parameters. The manufacturing method for the Ti64 alloy does not affect the minimum chip thickness (MCT) and the MCT for both the SLM and wrought is 1 μm/tooth. SLM parts exhibit acicular α martensitic grains, which result in higher hardness and tensile strength. This phenomenon prolongs the transition zone of micro-milling for the formation of minimum chip thickness. Additionally, the average cutting force values for SLM and wrought Ti64 fluctuated between 0.072 N and 1.96 N, depending on the micro milling parameters used. Finally, it is worth noting that micro-milled SLM workpieces exhibit lower areal surface roughness than wrought ones. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

14 pages, 6959 KiB  
Article
Mechanical and Thermal Properties of the High Thermal Conductivity Steel (HTCS) Additively Manufactured via Powder-Fed Direct Energy Deposition
by Jong-Youn Son, Ki-Yong Lee, Gwang-Yong Shin, Chang-Hwan Choi and Do-Sik Shim
Micromachines 2023, 14(4), 872; https://doi.org/10.3390/mi14040872 - 18 Apr 2023
Cited by 3 | Viewed by 1537
Abstract
High thermal conductivity steel (HTCS-150) is deposited onto non-heat-treated AISI H13 (N-H13) via powder-fed direct energy deposition (DED) based on the response surface methodology (RSM) to enhance the mechanical properties and thermal conductivity of N-H13, which is generally used as a hot-work tool [...] Read more.
High thermal conductivity steel (HTCS-150) is deposited onto non-heat-treated AISI H13 (N-H13) via powder-fed direct energy deposition (DED) based on the response surface methodology (RSM) to enhance the mechanical properties and thermal conductivity of N-H13, which is generally used as a hot-work tool steel. The main process parameters of the powder-fed DED are priorly optimized to minimize defects in the deposited regions and, therefore, to obtain homogeneous material properties. The deposited HTCS-150 is comprehensively evaluated through hardness, tensile, and wear tests at the different temperatures of 25, 200, 400, 600, and 800 °C. Compared to conventionally heat-treated (quenched and tempered) H13 (HT-H13), the hardness of the additively manufactured HTCS-150 slightly increases at 25 °C, whereas it does not show any significant difference above 200 °C. However, the HTCS-150 deposited on N-H13 shows a lower ultimate tensile strength and elongation than HT-H13 at all tested temperatures, and the deposition of the HTCS-150 on N-H13 enhances the ultimate tensile strength of N-H13. While the HTCS-150 does not show a significant difference in the wear rate below 400 °C compared to HT-H13, it shows a lower wear rate above 600 °C. The HTCS-150 reveals a higher thermal conductivity than the HT-H13 below 600 °C, whereas the behavior is reversed at 800 °C. The results suggest that the HTCS-150 additively manufactured via powder-fed direct energy deposition can enhance the mechanical and thermal properties of N-H13, including hardness, tensile strength, wear resistance, and thermal conductivity in a wide range of temperatures, often superior to those of HT-H13. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

13 pages, 3988 KiB  
Article
Influence of Post Heat Treatment Condition on Corrosion Behavior of 18Ni300 Maraging Steel Manufactured by Laser Powder Bed Fusion
by Kichang Bae, Dongmin Shin, Jun-Ho Kim, Wookjin Lee, Ilguk Jo and Junghoon Lee
Micromachines 2022, 13(11), 1977; https://doi.org/10.3390/mi13111977 - 15 Nov 2022
Cited by 2 | Viewed by 1264
Abstract
Laser powder bed fusion (LPBF) is a promising additive-manufacturing process for metallic materials. It has the advantage of flexibility in product design, such that various mechanical parts can be fabricated. However, because metal parts are built-up in a layer-by-layer manner, the material fabricated [...] Read more.
Laser powder bed fusion (LPBF) is a promising additive-manufacturing process for metallic materials. It has the advantage of flexibility in product design, such that various mechanical parts can be fabricated. However, because metal parts are built-up in a layer-by-layer manner, the material fabricated by LPBF has an anisotropic microstructure, which is important for the design of materials. In this study, the corrosion resistance of 18Ni300 maraging steel (MS) fabricated by LPBF was explored considering the building direction. Furthermore, the effects of heat treatment and aging on the microstructure and corrosion resistance were investigated. Sub-grain cells formed by rapid cooling in LPBF improve the corrosion resistance of MS. As a result, the as-built MS has the highest corrosion resistance. However, the sub-grain cells are eliminated by heat treatment or aging, which causes the deterioration of corrosion resistance. In the case of 18Ni300 MS, the cylindrical sub-grain cells are formed and aligned along the heat dissipation direction, which is similar to the building direction; thus, a significant anisotropy in corrosion resistance is found in the as-built MS. However, such anisotropy in corrosion resistance is diminished by heat treatment and aging, which eliminates the sub-grain cells. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

16 pages, 7080 KiB  
Article
The Effects of Heat Treatment on Microstructure and Mechanical Properties of Selective Laser Melting 6061 Aluminum Alloy
by Wei Liu, Shan Huang, Shuangsong Du, Ting Gao, Zhengbin Zhang, Xuehui Chen and Lei Huang
Micromachines 2022, 13(7), 1059; https://doi.org/10.3390/mi13071059 - 30 Jun 2022
Cited by 2 | Viewed by 2560
Abstract
Selective laser melting technology can be used for forming curved panels of 6061 aluminum alloy thermal shield devices for the International Thermonuclear Experimental Reactor (ITER), in order to make the formed parts with better performance. This study proposes different heat treatment processes, including [...] Read more.
Selective laser melting technology can be used for forming curved panels of 6061 aluminum alloy thermal shield devices for the International Thermonuclear Experimental Reactor (ITER), in order to make the formed parts with better performance. This study proposes different heat treatment processes, including annealed treatment at 300 °C for 2 h, solution treatment at 535 °C and then aging at 175 °C over 2 h, to control the mechanical behavior of the 6061 aluminum alloy samples prepared by selective laser melting (SLM). The mechanical properties such as ductility, tensile strength, and hardness of SLM 6061 aluminum alloy were investigated, and the microstructure of the samples was analyzed. The eutectic silicon skeleton shape disappeared after annealing treatment at 300 °C for 2 h. The tensile strength decreased by 22.86% (from 315 MPa to 243 MPa of the deposited state samples), and the elongation increased from 2.01% to 6.89%. Moreover, the hardness reduced from 120.07 HV0.2 to 89.6 HV0.2. After solution aging, the unique microstructure of SLM disappeared. Furthermore, the precipitation of massive Si particles on the α-Al matrix increased, and a trace amount of the Mg2Si(β) phase was generated. Compared with the deposited samples, the tensile strength decreased by 12.06%, while the hardness of specimens was 118.8 HV0.2. However, the elongation showed a remarkable increase of 297% (from 2.01% to 7.97%). Therefore, solution aging can critically improve the plasticity without losing significant tensile stress in the SLM 6061 aluminum alloy. This study proposes the use of SLM 6061 aluminum alloy for the thermal shields on the ITER and provides a reference for choosing a reasonable heat-treatment method for the optimal performance of the SLM 6061 aluminum alloy. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

9 pages, 4918 KiB  
Article
Study on Microstructure and Properties of Ni60A/WC Composite Coating by Alternating-Magnetic-Field-Assisted Laser Cladding
by Yuxu Zhu, Houming Zhou, Zixin Chen, Zeda Wang, Fangjia He and Caixing Xu
Micromachines 2022, 13(5), 653; https://doi.org/10.3390/mi13050653 - 20 Apr 2022
Cited by 5 | Viewed by 1755
Abstract
Ni60A/WC composite coating is prepared on 45 steel substrate by alternating-magnetic-field-assisted laser cladding. We compare the effects of different magnetic field intensity on WC particle distribution, microstructure, phase composition, microhardness and wear; in addition, the mechanism of alternating magnetic fields on cladding layers [...] Read more.
Ni60A/WC composite coating is prepared on 45 steel substrate by alternating-magnetic-field-assisted laser cladding. We compare the effects of different magnetic field intensity on WC particle distribution, microstructure, phase composition, microhardness and wear; in addition, the mechanism of alternating magnetic fields on cladding layers is briefly analyzed. The results show that an alternating magnetic field can significantly homogenize the distribution of WC particles. WC particles at the bottom are stirred and dispersed to the middle and upper area of the laser pool. The distribution of WC in the bottom region 6 of the coating decreases from 19.1% to 10%, the distribution of WC in the bottom region 5 decreases from 46.46% to 33.3%, the WC distribution in the top region 1 of the coating increases from 0 to 7.7% and the WC distribution in the top region 2 of the coating increases from 8.08% to 12.2%. The stirring of alternating magnetic fields strengthens the solute convection in the laser pool, refines the snowflake-shaped carbide hard phase and improves the coating microhardness and wear property, and adhesive wear and abrasive wear decrease gradually with increasing magnetic field strength. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

15 pages, 5091 KiB  
Article
Additive Manufacturing of Textured FePrCuB Permanent Magnets
by Dagmar Goll, Felix Trauter, Ralf Loeffler, Thomas Gross and Gerhard Schneider
Micromachines 2021, 12(9), 1056; https://doi.org/10.3390/mi12091056 - 31 Aug 2021
Cited by 9 | Viewed by 2760
Abstract
Permanent magnets based on FePrCuB were realized on a laboratory scale through additive manufacturing (laser powder bed fusion, L-PBF) and book mold casting (reference). A well-adjusted two-stage heat treatment of the as-cast/as-printed FePrCuB alloys produces hard magnetic properties without the need for subsequent [...] Read more.
Permanent magnets based on FePrCuB were realized on a laboratory scale through additive manufacturing (laser powder bed fusion, L-PBF) and book mold casting (reference). A well-adjusted two-stage heat treatment of the as-cast/as-printed FePrCuB alloys produces hard magnetic properties without the need for subsequent powder metallurgical processing. This resulted in a coercivity of 0.67 T, remanence of 0.67 T and maximum energy density of 69.8 kJ/m3 for the printed parts. While the annealed book-mold-cast FePrCuB alloys are easy-plane permanent magnets (BMC magnet), the printed magnets are characterized by a distinct, predominantly directional microstructure that originated from the AM process and was further refined during heat treatment. Due to the higher degree of texturing, the L-PBF magnet has a 26% higher remanence compared to the identically annealed BMC magnet of the same composition. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

14 pages, 8333 KiB  
Article
Additive Manufacturing of Bulk Nanocrystalline FeNdB Based Permanent Magnets
by Dagmar Goll, Felix Trauter, Timo Bernthaler, Jochen Schanz, Harald Riegel and Gerhard Schneider
Micromachines 2021, 12(5), 538; https://doi.org/10.3390/mi12050538 - 10 May 2021
Cited by 21 | Viewed by 3544
Abstract
Lab scale additive manufacturing of Fe-Nd-B based powders was performed to realize bulk nanocrystalline Fe-Nd-B based permanent magnets. For fabrication a special inert gas process chamber for laser powder bed fusion was used. Inspired by the nanocrystalline ribbon structures, well-known from melt-spinning, the [...] Read more.
Lab scale additive manufacturing of Fe-Nd-B based powders was performed to realize bulk nanocrystalline Fe-Nd-B based permanent magnets. For fabrication a special inert gas process chamber for laser powder bed fusion was used. Inspired by the nanocrystalline ribbon structures, well-known from melt-spinning, the concept was successfully transferred to the additive manufactured parts. For example, for Nd16.5-Pr1.5-Zr2.6-Ti2.5-Co2.2-Fe65.9-B8.8 (excess rare earth (RE) = Nd, Pr; the amount of additives was chosen following Magnequench (MQ) powder composition) a maximum coercivity of µ0Hc = 1.16 T, remanence Jr = 0.58 T and maximum energy density of (BH)max = 62.3 kJ/m3 have been achieved. The most important prerequisite to develop nanocrystalline printed parts with good magnetic properties is to enable rapid solidification during selective laser melting. This is made possible by a shallow melt pool during laser melting. Melt pool depths as low as 20 to 40 µm have been achieved. The printed bulk nanocrystalline Fe-Nd-B based permanent magnets have the potential to realize magnets known so far as polymer bonded magnets without polymer. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

Review

Jump to: Research

17 pages, 3418 KiB  
Review
A Review of Research Progress in Selective Laser Melting (SLM)
by Bingwei Gao, Hongjian Zhao, Liqing Peng and Zhixin Sun
Micromachines 2023, 14(1), 57; https://doi.org/10.3390/mi14010057 - 25 Dec 2022
Cited by 28 | Viewed by 6520
Abstract
SLM (Selective Laser Melting) is a unique additive manufacturing technology which plays an irreplaceable role in the modern industrial revolution. 3D printers can directly process metal powder quickly to obtain the necessary parts faster. Shortly, it will be possible to manufacture products at [...] Read more.
SLM (Selective Laser Melting) is a unique additive manufacturing technology which plays an irreplaceable role in the modern industrial revolution. 3D printers can directly process metal powder quickly to obtain the necessary parts faster. Shortly, it will be possible to manufacture products at unparalleled speeds. Advanced manufacturing technology is used to produce durable and efficient parts with different metals that have good metal structure performance and excellent metal thermal performance, to lead the way for laser powder printing technology. Traditional creative ways are usually limited by time, and cannot respond to customers’ needs fast enough; for some parts with high precision and complexity, conventional manufacturing methods are inadequate. Contrary to this, SLM technology offers some advantages, such as requiring no molds this decreases production time and helps to reduce costs. In addition, SLM technology has strong comprehensive functions, which can reduce assembly time and improve material utilization. Parts with complex structures, such as cavities and three-dimensional grids, can be made without restricting the shape of products. Products or parts can be printed quickly without the use of expensive production equipment. The product quality is better, and the mechanical load performance is comparable to traditional production technologies (such as forging). This paper introduces in detail the process parameters that affect SLM technology and how they affect SLM, commonly used metal materials and non-metallic materials, and summarizes the current research. Finally, the problems faced by SLM are prospected. Full article
(This article belongs to the Special Issue Laser Additive Manufacturing of Metallic Materials)
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-10
Back to TopTop