Special Issue "Metal Materials and Non-conventional Mechanical Manufacturing Processes"

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (8 May 2019).

Special Issue Editors

Prof. Dr. Luis Norberto López de Lacalle
E-Mail Website
Guest Editor
Department of Mechanical Engineering (High Performance Manufacturing Group), University of the Basque Country (UPV/EHU), Parque Tecnológico de Zamudio 202, 48170 Bilbao, Spain
Interests: manufacturing process; aeronautics; machine tools; Industry 4.0; machining
Special Issues and Collections in MDPI journals
Dr. Antonio J. Sánchez Egea
E-Mail Website
Guest Editor
Centre of Advanced Manufacturing Technologies for Aeronautics CFAA; Department of Mechanical Engineering, University of the Basque Country; EIB, Alameda de Urquijo s/n, 48013 Bilbao, Spain
Interests: hybrid manufacturing; machine tools; modelling; non-conventinal manufacturing processes; material texturing
Dr. Octavio Pereira Neto
E-Mail Website
Guest Editor
High Performance Manufacturing research group, Department of Mechanical Engineering, University of the Basque Country; EIB, Alameda de Urquijo s/n, 48013 Bilbao, Spain
Interests: green manufactuing; lubri-cooling processes; cryogenics manufacturing processes; friction and wear; rheology; coatings; life cycle assessment
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

Automotive, aeronautics, windmill, tooling industry and bioengineering instruments are causing the spread of applications and ideas in the field of non-conventional manufacturing processes. All the novel proposals imply new mechanical and materials challenges for performing effective manufacturing processes. To this end, new processes involve technical modifications in machines and/or auxiliary devices to achieve other capabilities. Additionally, new approaches result from the combination of simpler ones. There are several terms in: PECM (Pulse Electrochemical Machining), ECM (Electrochemical Machining), EDM (Electrical Discharge Machining), biomachining, electrically-assisted machining, laser-assisted machining, etc. Each of these novel techniques involve the control of operational parameters, modifications in machines and accessories and some proofs of concepts. This Special Issue covers the topics listed in keywords below.

This Special Issue aims the latest advances in metal materials and non-conventional mechanical manufacturing processes. Contributions are welcome from both academic researchers and their industrial peers, dealing with innovating novel non-conventional manufacturing applications.

Prof. Dr. Luis Norberto López de Lacalle
Dr. Antonio J. Sanchez Egea
Dr. Octavio Pereira Neto
Guest Editor

Manuscript Submission Information

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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. Materials 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 1800 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

  • New composites manufacturing processes
  • Hybrid approaches and machines for difficult-to-cut alloys
  • Recent advances on machine tool for high performance machining
  • Assisted machining methods: Vibration, electrical current, laser, etc.
  • Radical new processes for manufacturing
  • Electrical, electrochemical, chemical and biomachining
  • Life cycle analysis of new manufacturing processes
  • Auxiliary devices for hybrid manufacturing processes
  • Manufacturing of scientific instruments
  • Examples of challenging application in emerging niches: Dental, prosthesis, energy, science, etc.

Published Papers (8 papers)

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Research

Open AccessArticle
Rapid Alloy Development of Extremely High-Alloyed Metals Using Powder Blends in Laser Powder Bed Fusion
Materials 2019, 12(10), 1706; https://doi.org/10.3390/ma12101706 - 26 May 2019
Cited by 1
Abstract
The design of new alloys by and for metal additive manufacturing (AM) is an emerging field of research. Currently, pre-alloyed powders are used in metal AM, which are expensive and inflexible in terms of varying chemical composition. The present study describes the adaption [...] Read more.
The design of new alloys by and for metal additive manufacturing (AM) is an emerging field of research. Currently, pre-alloyed powders are used in metal AM, which are expensive and inflexible in terms of varying chemical composition. The present study describes the adaption of rapid alloy development in laser powder bed fusion (LPBF) by using elemental powder blends. This enables an agile and resource-efficient approach to designing and screening new alloys through fast generation of alloys with varying chemical compositions. This method was evaluated on the new and chemically complex materials group of multi-principal element alloys (MPEAs), also known as high-entropy alloys (HEAs). MPEAs constitute ideal candidates for the introduced methodology due to the large space for possible alloys. First, process parameters for LPBF with powder blends containing at least five different elemental powders were developed. Secondly, the influence of processing parameters and the resulting energy density input on the homogeneity of the manufactured parts were investigated. Microstructural characterization was carried out by optical microscopy, electron backscatter diffraction (EBSD), and energy-dispersive X-ray spectroscopy (EDS), while mechanical properties were evaluated using tensile testing. Finally, the applicability of powder blends in LPBF was demonstrated through the manufacture of geometrically complex lattice structures with energy absorption functionality. Full article
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Open AccessArticle
On-Line Monitoring of Blind Fastener Installation Process
Materials 2019, 12(7), 1157; https://doi.org/10.3390/ma12071157 - 10 Apr 2019
Abstract
Blind fasteners are of special interest for aircraft construction since they allow working on joints where only one side is accessible, as is the case in many common aerospace box-type structures, such as stabilizers and flaps. This paper aims to deliver an online [...] Read more.
Blind fasteners are of special interest for aircraft construction since they allow working on joints where only one side is accessible, as is the case in many common aerospace box-type structures, such as stabilizers and flaps. This paper aims to deliver an online monitoring method for the detection of incorrect installed blind fasteners. In this type of fastener, the back side of the assembly is not accessible, so monitoring the process installation is suitable as a system to assess the formed head at the back side with no access. The solution proposed consists of an on-line monitoring system that is based on sensor signals acquired during the installation. The signals are conveniently analyzed in order to provide an evaluation outcome on how the fastener was installed. This new method will help production to decrease/eliminate time and cost-intensive inspections and fasteners over installation in structures. The decrease of the number of installed fasteners will also contribute to weight savings and will reduce the use of resources. Full article
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Open AccessArticle
A Study on the Thermal Effect by Multi Heat Sources and Machining Characteristics of Laser and Induction Assisted Milling
Materials 2019, 12(7), 1032; https://doi.org/10.3390/ma12071032 - 28 Mar 2019
Cited by 1
Abstract
Thermally assisted machining (TAM) is an effective method for difficult-to-cut materials, and works by locally preheating the workpiece using various heat sources, such as laser, induction, and plasma. Recently, many researchers have studied TAM because of its low manufacturing costs, high productivity, and [...] Read more.
Thermally assisted machining (TAM) is an effective method for difficult-to-cut materials, and works by locally preheating the workpiece using various heat sources, such as laser, induction, and plasma. Recently, many researchers have studied TAM because of its low manufacturing costs, high productivity, and quality of materials. Laser assisted machining (LAM) has been studied by many researchers, but studies on TAM using induction or plasma heat sources, which are much cheaper than lasers, have been carried out by only a few researchers. Lasers have an excellent preheating effect, but are expensive, and the temperature of the heated workpiece drops quickly. Here, multi heat sources were used to solve the shortage in supplied heat source with a single heat source. Induction was applied as an additional heat source. The purpose of this study is to analyze the thermal effect and temperature distribution of single heat source and multi heat sources, and compare the machining characteristics according to heat source types. In order to analyze the preheating effect according to the feed rate of the heat sources, a temperature measurement experiment using thermocouples was carried out, and the efficiency of the thermal effect using multi heat sources was verified. In addition, the effectiveness of the thermal analysis results was verified by comparison with the measured temperature distribution. The machining characteristics of Inconel 718 and Ti-6Al-4V with laser, induction, and laser-induction assisted milling (LIAMill) were analyzed, by cutting force and surface roughness. Full article
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Open AccessArticle
Current-Induced Ductility Enhancement of a Magnesium Alloy AZ31 in Uniaxial Micro-Tension Below 373 K
Materials 2019, 12(1), 111; https://doi.org/10.3390/ma12010111 - 31 Dec 2018
Cited by 2
Abstract
The size effects in metal forming have been found to be crucial in micro-scale plastic deformation or micro-forming processes, which lead to attenuation of the material’s formability due to the increasing heterogeneity of the plastic flow. The use of an electric field during [...] Read more.
The size effects in metal forming have been found to be crucial in micro-scale plastic deformation or micro-forming processes, which lead to attenuation of the material’s formability due to the increasing heterogeneity of the plastic flow. The use of an electric field during micro-scale plastic deformation has shown to relieve size effects, enhance the material’s formability, modify the microstructure, etc. Consequently, these electric-assisted (EA) micro-forming processes seem to bring many potential benefits that need to be investigated. Accordingly, here we investigated the influence of an electric field on the size effects to describe the fracture behavior in uniaxial micro-tension tests of an AZ31 alloy with various grain sizes. In order to decouple the thermal-mechanical and microstructure changes, room temperature (RT), oven-heated (OH), air-cooled (AC), and EA uniaxial micro-tension tests were conducted. The size effects contribution on the fracture stress and strain showed a similar trend in all the testing configurations. However, the smallest fracture stresses and the largest fracture strains were denoted in the EA configuration. EBSD examination shows that current-induced dynamic recrystallization (DRX) and texture evolution could be negligible under the studied conditions. The kernel average misorientation (KAM) maps give the larger plastic deformation in the EA specimens due to the reduction of plastic micro-heterogeneity. Finally, the fracture morphology indicates that the current-induced ductility enhancement may be attributed to the arrest of micro-crack propagation and the inhibition of void initiation, growth, and coalescence caused by lattice melting and expansion. Full article
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Open AccessArticle
Comparative Analysis of Mechanical Properties and Metal-Ceramic Bond Strength of Co-Cr Dental Alloy Fabricated by Different Manufacturing Processes
Materials 2018, 11(10), 1801; https://doi.org/10.3390/ma11101801 - 22 Sep 2018
Cited by 5
Abstract
Cobalt-chromium (Co-Cr) alloy is a widely used base material for dental fixed prostheses. These restorations can be produced through casting technique, subtractive or additive manufacturing technologies. However, limited information is available regarding the influence of manufacturing techniques on the properties of Co-Cr alloy [...] Read more.
Cobalt-chromium (Co-Cr) alloy is a widely used base material for dental fixed prostheses. These restorations can be produced through casting technique, subtractive or additive manufacturing technologies. However, limited information is available regarding the influence of manufacturing techniques on the properties of Co-Cr alloy since most studies used different chemical compositions of Co-Cr alloy for different manufacturing methods. This study compares the mechanical properties, metal-ceramic bond strength, and microstructures of specimens produced by casting, milling, and selective laser melting (SLM) from one single Co-Cr alloy composition. The mechanical properties of the alloy were investigated by tensile and Vickers hardness tests, and metal-ceramic bond strength was determined by three-point bending. Scanning electron microscopy (SEM) with backscattered electron (BSE) images and optical microphotographs were used to analyze the surface microstructures. Compared with the casting and milling techniques, SLM Co-Cr alloy specimens indicated enhanced mechanical properties and comparable metal-ceramic bond strength. Besides, the microstructures of the SLM specimens showed finer grains with more second phase particles than the casting and milling specimens. The results of our study indicate that SLM might be superior to traditional techniques for the manufacturing of fixed dental restorations. Full article
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Open AccessArticle
An Innovative Method for Forming Balls by Cross Rolling
Materials 2018, 11(10), 1793; https://doi.org/10.3390/ma11101793 - 21 Sep 2018
Cited by 1
Abstract
The paper describes an innovative cross rolling method that enables the production of six balls at the same time, each ball with a diameter of 100 mm. The principle of the proposed rolling technique is discussed and the tools used in this forming [...] Read more.
The paper describes an innovative cross rolling method that enables the production of six balls at the same time, each ball with a diameter of 100 mm. The principle of the proposed rolling technique is discussed and the tools used in this forming process are described. Two variations of the proposed method for producing balls were investigated, one performed with the use of flat tools and the other with the use of two rolls. Results of the numerical modelling are discussed. They clearly demonstrate that the proposed method can be used to produce balls with large diameters. Rolling experiments were performed under laboratory conditions to produce 40 mm diameter balls, i.e., in the 1:2.5 scale. The experimental findings show a good qualitative agreement with the numerical results. Full article
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Open AccessArticle
Effect of Die Geometry on the Formability of 5052 Aluminum Alloy in Electromagnetic Impaction Deformation
Materials 2018, 11(8), 1379; https://doi.org/10.3390/ma11081379 - 08 Aug 2018
Cited by 2
Abstract
The formability of aluminum alloy sheet in electromagnetic impaction deformation has attracted the attention of numerous researchers for the past decades. However, the influences of die geometry and high-speed impaction electromagnetic deformation on formability have not been well established, thereby resulting in the [...] Read more.
The formability of aluminum alloy sheet in electromagnetic impaction deformation has attracted the attention of numerous researchers for the past decades. However, the influences of die geometry and high-speed impaction electromagnetic deformation on formability have not been well established, thereby resulting in the formability of the sheet not being developed fully. In this study, the influence of die geometry on the formability of 5052 aluminum alloy in electromagnetic deformation was investigated by comparing the formability of 5052 aluminum alloys formed using a hemispherical die and a cylindrical die. The intriguing finding is that the formability of the 5052 aluminum alloy formed using a cylindrical die is considerably higher than that formed using a hemispherical die. Therefore, die geometry significantly influences the formability of 5052 aluminum alloy. The influence of die geometry on the formability of 5052 aluminum alloy in high-speed impaction electromagnetic deformation was explained in terms of strain rate, pressure stress, and stress state. This investigation enhances insight into the interaction between sheets and dies, and provides a reference for the studying influence of dies on the forming limit of sheets in high-speed impaction deformation. Full article
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Open AccessArticle
Numerical Simulation and Experimental Validation of Sheet Laser Forming Processes Using General Scanning Paths
Materials 2018, 11(7), 1262; https://doi.org/10.3390/ma11071262 - 23 Jul 2018
Abstract
This work presents numerical simulations and an experimental validation of sheet laser forming processes using general scanning paths with different laser beam operating parameters (i.e., power, diameter, and scanning speed) in two specific graphite coated stainless steel blanks (i.e., with thicknesses of 0.3 [...] Read more.
This work presents numerical simulations and an experimental validation of sheet laser forming processes using general scanning paths with different laser beam operating parameters (i.e., power, diameter, and scanning speed) in two specific graphite coated stainless steel blanks (i.e., with thicknesses of 0.3 mm and 0.6 mm for the AISI 302 and 304 alloys, respectively). To this end, three specific laser forming tests involving single S-shaped, multiple circular, and single piecewise linear scanning paths are carried out. On the other hand, the numerical simulation of these tests is performed via a coupled thermomechanical finite element formulation, accounting for large viscoplastic strains, temperature-dependent material properties, and convection-radiation phenomena. The final bending angles provided by this model are found to be in good agreement with the experimental measurements for all of the cases studied. Therefore, this modeling framework can be established as a reliable approach to predict the material thermomechanical response during sheet laser forming using general scanning paths. Full article
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