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Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization...
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Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: closed (31 July 2019) | Viewed by 47420

Special Issue Editors

Dr. Lonnie J. Love

E-Mail Website
Guest Editor
Manufacturing Systems Research Group, Oak Ridge National Laboratory, 2350 Cherahala Blvd, Knoxville TN, USA
Interests: design; robotics; hydraulics; additive manufacturing; nanomaterials
Special Issues, Collections and Topics in MDPI journals
Dr. Ryan R. Dehoff

E-Mail Website
Guest Editor
Manufacturing Systems Research Group, Oak Ridge National Laboratory, 2350 Cherahala Blvd, Knoxville, TN, USA
Interests: electron beam melting; laser metal deposition; ultrasonic additive manufacturing
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Metal additive manufacturing enables the rapid, low-volume production of highly complex metallic components. Numerous industries are highly interested in directly manufacturing metallic components, but there remains great uncertainty in terms of the processes and controls slowing widespread industrialization. This is complicated due to the tremendous flexibility in materials and processes, with each having their own strengths and weaknesses. Approaches vary from direct energy deposition, powder bed fusion, extrusion, and thermal and cold spray, to name just a few. Each of these processes, while simple in principle, exhibits its own complexity in terms of material properties that are a function of processing parameters, toolpaths, and systems and controls. In many cases, there seems to be more art than science when it comes to reliably being able to manufacture components using these advanced manufacturing processes. This uncertainty can lead to the slow adoption of the technologies in industrial settings.

We invite authors to contribute original research articles, as well as review articles, that will contribute to the area in metal additive manufacturing materials, processes, and controls.

Potential topics include, but are not limited to, the following:

  • Advanced materials for additive manufacturing;
  • Advanced metrology and control technology for metal additive manufacturing;
  • Data Analytics and AI approaches to partial certification and control;
  • New metal additive manufacturing processes.

Dr. Lonnie J. Love
Dr. Ryan R. Dehoff
Guest Editor

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. Applied Sciences is an international peer-reviewed open access semimonthly 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 2400 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

  • Metal additive manufacturing;
  • Metrology;
  • Data analytics;
  • Machine learning.

Published Papers (10 papers)

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Research

17 pages, 9363 KiB  
Article
Effect of Interlayer Cooling Time, Constraint and Tool Path Strategy on Deformation of Large Components Made by Laser Metal Deposition with Wire
by Yousub Lee, Yashwanth Bandari, Peeyush Nandwana, Brian. T. Gibson, Brad Richardson and Srdjan Simunovic
Appl. Sci. 2019, 9(23), 5115; https://doi.org/10.3390/app9235115 - 26 Nov 2019
Cited by 27 | Viewed by 3309
Abstract
Laser metal deposition with wire (LMD-w) is a developing additive manufacturing (AM) technology that has a high deposition material rate and efficiency and is suitable for fabrication of large aerospace components. However, control of material properties, geometry, and residual stresses is needed before [...] Read more.
Laser metal deposition with wire (LMD-w) is a developing additive manufacturing (AM) technology that has a high deposition material rate and efficiency and is suitable for fabrication of large aerospace components. However, control of material properties, geometry, and residual stresses is needed before LMD-w technology can be widely adopted for the construction of critical structural components. In this study, we investigated the effect of interlayer cooling time, clamp constraints, and tool path strategy on part distortion and residual stresses in large-scale laser additive manufactured Ti-6Al-4V components using finite element method (FEM). The simulations were validated with the temperature and the distortion measurements obtained from a real LMD-w process. We found that a shorter interlayer cooling time, full clamping constraints on the build plates, and a bidirectional tool path with 180° rotation minimized part distortion and residual stresses and resulted in symmetric stress distribution. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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28 pages, 27974 KiB  
Article
Processing of Alnico Magnets by Additive Manufacturing
by Emma White, Emily Rinko, Timothy Prost, Timothy Horn, Christopher Ledford, Christopher Rock and Iver Anderson
Appl. Sci. 2019, 9(22), 4843; https://doi.org/10.3390/app9224843 - 12 Nov 2019
Cited by 24 | Viewed by 5560
Abstract
Permanent magnets without rare earth (RE) elements, such as alnico, will improve supply stability and potentially decrease permanent magnet cost, especially for traction drive motors and other increased temperature applications. Commercial alnico magnets with the highest energy product are produced by directional solidification [...] Read more.
Permanent magnets without rare earth (RE) elements, such as alnico, will improve supply stability and potentially decrease permanent magnet cost, especially for traction drive motors and other increased temperature applications. Commercial alnico magnets with the highest energy product are produced by directional solidification (DS) to achieve a <001> columnar grain orientation followed by significant final machining, adding to the high cost. Additive manufacturing (AM) is an effective method to process near net-shape parts with minimal final machining of complex geometries. AM also, has potential for texture/grain orientation control and compositionally graded structures. This report describes fabrication of alnico magnets by AM using both laser engineered net shaping (LENS)/directed energy deposition (DED) and electron beam melting powder bed fusion (EBM/PBF). High pressure gas atomized (HPGA) pre-alloyed alnico powders, with high purity and sphericity, were built into cylindrical and rectangular samples, followed by magnetic annealing (MA) and a full heat treatment (FHT). The magnetic properties of these AM processed specimens were different from their cast and sintered counterparts of the same composition and show a great sensitivity to heat treatment. The AM process parameters used in this developmental study did not yet result in any preferred texture within the alnico AM builds. These findings demonstrate feasibility for near net-shape processing of alnico permanent magnets for use in next generation traction drive motors and other applications requiring increased operating temperatures and/or complex engineered part geometries, especially with further AM process development for texture control. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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14 pages, 3869 KiB  
Article
Beyond the Toolpath: Site-Specific Melt Pool Size Control Enables Printing of Extra-Toolpath Geometry in Laser Wire-Based Directed Energy Deposition
by Brian T. Gibson, Bradley S. Richardson, Tayler W. Sundermann and Lonnie J. Love
Appl. Sci. 2019, 9(20), 4355; https://doi.org/10.3390/app9204355 - 16 Oct 2019
Cited by 14 | Viewed by 3084
Abstract
A variety of techniques have been utilized in metal additive manufacturing (AM) for melt pool size management, including modeling and feed-forward approaches. In a few cases, closed-loop control has been demonstrated. In this research, closed-loop melt pool size control for large-scale, laser wire-based [...] Read more.
A variety of techniques have been utilized in metal additive manufacturing (AM) for melt pool size management, including modeling and feed-forward approaches. In a few cases, closed-loop control has been demonstrated. In this research, closed-loop melt pool size control for large-scale, laser wire-based directed energy deposition is demonstrated with a novel modification, i.e., site-specific changes to the controller setpoint were commanded at trigger points, the locations of which were generated by the projection of a secondary geometry onto the primary three-dimensional (3D) printed component geometry. The present work shows that, through this technique, it is possible to print a specific geometry that occurs beyond the actual toolpath of the print head. This is denoted as extra-toolpath geometry and is fundamentally different from other methods of generating component features in metal AM. A proof-of-principle experiment is presented in which a complex oak leaf geometry was embossed on an otherwise ordinary double-bead wall made from Ti-6Al-4V. The process is introduced and characterized primarily from a controls perspective with reports on the performance of the control system, the melt pool size response, and the resulting geometry. The implications of this capability, which extend beyond localized control of bead geometry to the potential mitigations of defects and functional grading of component properties, are discussed. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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22 pages, 7757 KiB  
Article
Characteristics and Processing of Hydrogen-Treated Copper Powders for EB-PBF Additive Manufacturing
by Christopher Ledford, Christopher Rock, Paul Carriere, Pedro Frigola, Diana Gamzina and Timothy Horn
Appl. Sci. 2019, 9(19), 3993; https://doi.org/10.3390/app9193993 - 24 Sep 2019
Cited by 27 | Viewed by 7680
Abstract
The fabrication of high purity copper using additive manufacturing has proven difficult because of oxidation of the powder feedstock. Here, we present work on the hydrogen heat treatment of copper powders for electron beam powder bed fusion (EB-PBF), in order to enable the [...] Read more.
The fabrication of high purity copper using additive manufacturing has proven difficult because of oxidation of the powder feedstock. Here, we present work on the hydrogen heat treatment of copper powders for electron beam powder bed fusion (EB-PBF), in order to enable the fabrication of high purity copper components for applications such as accelerator components and vacuum electronic devices. Copper powder with varying initial oxygen contents were hydrogen heat-treated and characterized for their chemistry, morphology, and microstructure. Higher initial oxygen content powders were found to not only reduce surface oxides, but also reduce oxides along the grain boundaries and form trapped H2O vapor inside the particles. The trapped H2O vapor was verified by thermogravimetric analysis (TGA) and residual gas analysis (RGA) while melting. The mechanism of the H2O vapor escaping the particles was determined by in-situ SEM heated stage experiments, where the particles were observed to crack along the grain boundaries. To determine the effect of the EB-PBF processing on the H2O vapor, the thermal simulation and the validation of single melt track width wafers were conducted along with melting single layer discs for chemistry analysis. A high speed video of the EB-PBF melting was performed in order to determine the effect of the trapped H2O vapor on the melt pool. Finally, solid samples were fabricated from hydrogen-treated copper powder, where the final oxygen content measured ~50 wt. ppm, with a minimal residue hydrogen content, indicating the complete removal of trapped H2O vapor from the solid parts. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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11 pages, 13449 KiB  
Article
Grain Size Effects in Selective Laser Melted Fe-Co-2V
by Wesley Everhart and Joseph Newkirk
Appl. Sci. 2019, 9(18), 3701; https://doi.org/10.3390/app9183701 - 06 Sep 2019
Cited by 16 | Viewed by 2484
Abstract
The material science of additive manufacturing (AM) has become a significant topic due to the unique way in which the material and geometry are created simultaneously. Major areas of research within inorganic materials include traditional structural materials, shape memory alloys, amorphous materials, and [...] Read more.
The material science of additive manufacturing (AM) has become a significant topic due to the unique way in which the material and geometry are created simultaneously. Major areas of research within inorganic materials include traditional structural materials, shape memory alloys, amorphous materials, and some new work in intermetallics. The unique thermal profiles created during selective laser melting (SLM) may provide new opportunities for processing intermetallics to improve mechanical and magnetic performance. A parameter set for the production of Fe-Co-2V material with additive manufacturing is developed and efforts are made to compare the traditional wrought alloy to the AM version of the same chemistry. Evaluation includes magnetic properties, composition, and phase as a function of thermal history, as well as mechanical performance. Results show significant similarities in microstructure between AM and wrought materials, as well as mechanical and magnetic performance. Property trends are evaluated as a function of grain size and show effects similar to the Hall–Petch strengthening observed in wrought material, though with some underprediction of the strength. Magnetic properties qualitatively follow the expected trends but demonstrate some deviation from wrought material, which is still unexplained. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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15 pages, 4192 KiB  
Article
Additive Friction Stir-Enabled Solid-State Additive Manufacturing for the Repair of 7075 Aluminum Alloy
by R. Joey Griffiths, Dylan T. Petersen, David Garcia and Hang Z. Yu
Appl. Sci. 2019, 9(17), 3486; https://doi.org/10.3390/app9173486 - 23 Aug 2019
Cited by 77 | Viewed by 7429
Abstract
The repair of high strength, high performance 7075 aluminum alloy is essential for a broad range of aerospace and defense applications. However, it is challenging to implement it using traditional fusion welding-based approaches, owing to hot cracking and void formation during solidification. Here, [...] Read more.
The repair of high strength, high performance 7075 aluminum alloy is essential for a broad range of aerospace and defense applications. However, it is challenging to implement it using traditional fusion welding-based approaches, owing to hot cracking and void formation during solidification. Here, the use of an emerging solid-state additive manufacturing technology, additive friction stir deposition, is explored for the repair of volume damages such as through -holes and grooves in 7075 aluminum alloy. Three repair experiments have been conducted: double through-hole filling, single through-hole filling, and long, wide-groove filling. In all experiments, additive friction stir deposition proves to be effective at filling the entire volume. Additionally, sufficient mixing between the deposited material and the side wall of the feature is always observed in the upper portions of the repair. Poor mixing and inadequate repair quality have been observed in deeper portions of the filling in some scenarios. Based on these observations, the advantages and disadvantages of using additive friction stir deposition for repairing volume damages are discussed. High quality and highly flexible repairs are expected with systematic optimization work on process control and repair strategy development in the future. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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15 pages, 7981 KiB  
Article
Direct-Write Dewetting of High Melting Temperature Metals on Flexible Substrates
by Anthony J. Ferrer, Anna Halajko and Glenn G. Amatucci
Appl. Sci. 2019, 9(15), 3165; https://doi.org/10.3390/app9153165 - 03 Aug 2019
Cited by 3 | Viewed by 2306
Abstract
Microelectromechanical systems (MEMS) are pervasive in modern technology due to their reliability, small foot print, and versatility of function. While many of the manufacturing techniques for MEMS devices stem from integrated circuit (IC) manufacturing, the wide range of designs necessitates more varied processing [...] Read more.
Microelectromechanical systems (MEMS) are pervasive in modern technology due to their reliability, small foot print, and versatility of function. While many of the manufacturing techniques for MEMS devices stem from integrated circuit (IC) manufacturing, the wide range of designs necessitates more varied processing techniques. Here, new details of a scanning laser based direct-write dewetting technique are presented as an expansion of previous demonstrations. For the first time, the ability to pattern a high melting temperature and high reflectance metallic thin films of Ni and Ag, respectively, on polymer substrates is reported. Novel methods for reducing the power necessary for processing highly reflective films are demonstrated by depositing very thin films of high near-infrared absorbance. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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16 pages, 4302 KiB  
Article
Finite Element Analysis of Thermal Stress and Thermal Deformation in Typical Part during SLM
by Peiying Bian, Xiaodong Shao and Jingli Du
Appl. Sci. 2019, 9(11), 2231; https://doi.org/10.3390/app9112231 - 30 May 2019
Cited by 25 | Viewed by 6235
Abstract
Selective laser melting (SLM) constitutes an additive manufacturing (AM) method. Many issues such as thermal strain and macro-thermal deformation, which are caused by the thermal stress of different process parameters, are not clear. In this paper, an efficient and fast manufacturing simulation method [...] Read more.
Selective laser melting (SLM) constitutes an additive manufacturing (AM) method. Many issues such as thermal strain and macro-thermal deformation, which are caused by the thermal stress of different process parameters, are not clear. In this paper, an efficient and fast manufacturing simulation method was researched based on a moving heat source model and an elastoplastic theory of welding simulation, which was studied based on the thermodynamic coupling algorithm with a software-developed application for the SLM process. Subsequently, typical case results of thin and hollow plate part formation and the corresponding performances were simulated in detail. The results demonstrated that the effective thermal stress increased as the layer height increased from the surface layer to the substrate, while the thermal strain followed an approximate change rule. In addition, the stress was released from the underlying substrate when the support was removed. Moreover, the largest single axis plane stress was changed from tension to compression from the edge to the center, finally reaching equilibrium. In particular, maximum macro thermal deformation occurred at the printed support structure to the samples, displaying similar results in other locations such as the corners. Finally, the effectiveness of the simulation could be verified from the realistic printed part, which could provide proof for the quality prediction of the part that is actually forming. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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16 pages, 9845 KiB  
Article
Simulation of Surface Topography Considering Cut-in Impact and Tool Flank Wear
by Haining Gao, Caixu Yue, Xianli Liu and Yuechong Nan
Appl. Sci. 2019, 9(4), 732; https://doi.org/10.3390/app9040732 - 20 Feb 2019
Cited by 15 | Viewed by 3472
Abstract
Milling is a kind of interrupted cutting. When the tool cuts into the workpiece, it is often accompanied by instantaneous impact, which results in impact vibration of the milling system. Meanwhile, tool wear will occur gradually on flank face with the cutting progress. [...] Read more.
Milling is a kind of interrupted cutting. When the tool cuts into the workpiece, it is often accompanied by instantaneous impact, which results in impact vibration of the milling system. Meanwhile, tool wear will occur gradually on flank face with the cutting progress. The impact vibration and tool wear affect the morphological characteristics of machined surfaces. In the present work, the instantaneous impact force is obtained by introducing the italic impact model of single degree of freedom, and the free vibration in the x and y directions under the impact force is obtained by combining the damped vibration equation. The cutting vibration in the x and y directions is obtained by solving the dynamic equation of the milling system with the fourth-order Runge–Kutta method. The equation of the cutting edge is modified according to the tool flank wear, and the machined surface topography considering the dynamic characteristics of cutting system and tool flank wear is obtained by combining the Z-MAP algorithm. The verification milling experiment was carried out on the hardened steel Cr12MoV workpiece. The simulation results are in good agreement with the experimental results. The research results have important guiding significance for the reasonable selection of processing parameters in actual production. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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14 pages, 3308 KiB  
Article
The Effects of Selective Laser Melting Process Parameters on Relative Density of the AlSi10Mg Parts and Suitable Procedures of the Archimedes Method
by Shigang Bai, Nataliya Perevoshchikova, Yu Sha and Xinhua Wu
Appl. Sci. 2019, 9(3), 583; https://doi.org/10.3390/app9030583 - 11 Feb 2019
Cited by 72 | Viewed by 5229
Abstract
In view of the importance of accurately measuring the relative density of a selective laser melted (SLMed) part for optimizing the selective laser melting (SLM) processing parameters, suitable procedures of the Archimedes method considering the surface-connected cavities were proposed by comparing the results [...] Read more.
In view of the importance of accurately measuring the relative density of a selective laser melted (SLMed) part for optimizing the selective laser melting (SLM) processing parameters, suitable procedures of the Archimedes method considering the surface-connected cavities were proposed by comparing the results using the Archimedes method with image analysis. The effects of the SLM processing parameters on the relative density of AlSi10Mg were investigated using the proposed procedures of the Archimedes methods and image analysis. Fourteen SLMed samples were produced by different SLM processing parameters according to Doehlert Matrix. The regression models correlating relative density and three SLM processing parameters (laser power, scan speed, and hatching distance) were built and the optimum parameter combination to get a high relative density was obtained. By plotting the response surfaces and contours of the regression models, it was found that the relative densities are both higher at the combination of the higher scan speed, higher power, and lower hatching distance and at the combination of a lower scan speed, a moderate laser power, and a optional hatching distance. It was also found that the parameter of hatching distance is the crucial parameter to get a high relative density and to get high mechanical property. Full article
(This article belongs to the Special Issue Additive Manufacturing of Metal Components: Mechanical Behavior, Process Parameter Optimization and Control)
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