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Additive manufacturing (AM) can be seen as a disruptive process that builds complex components layer upon layer. Two of its distinct technologies are Selective Laser Melting (SLM) and Electron Beam Melting (EBM), which are powder bed fusion processes that create metallic parts with the aid of a beam source. One of the most studied and manufactured superalloys in metal AM is the Ti–6Al–4V, which can be applied in the aerospace field due to its low density and high melting point, and in the biomedical area owing to its high corrosion resistance and excellent biocompatibility when in contact with tissues or bones of the human body. The research novelty of this work is the aggregation of all kinds of data from the last 20 years of investigation about Ti–6Al–4V parts manufactured via SLM and EBM, namely information related to residual stresses (RS), as well as the influence played by different heat treatments in reducing porosity and increasing mechanical properties. Throughout the report, it can be seen that the expected microstructure of the Ti–6Al–4V alloy is different in both manufacturing processes, mainly due to the distinct cooling rates. However, heat treatments can modify the microstructure, reduce RS, and increase the ductility, fatigue life, and hardness of the components. Furthermore, distinct post-treatments can induce compressive RS on the part’s surface, consequently enhancing the fatigue life.
Óscar Teixeira; Francisco J. G. Silva; Luís P. Ferreira; Eleonora Atzeni. A Review of Heat Treatments on Improving the Quality and Residual Stresses of the Ti–6Al–4V Parts Produced by Additive Manufacturing. Metals 2020, 10, 1006 .
AMA StyleÓscar Teixeira, Francisco J. G. Silva, Luís P. Ferreira, Eleonora Atzeni. A Review of Heat Treatments on Improving the Quality and Residual Stresses of the Ti–6Al–4V Parts Produced by Additive Manufacturing. Metals. 2020; 10 (8):1006.
Chicago/Turabian StyleÓscar Teixeira; Francisco J. G. Silva; Luís P. Ferreira; Eleonora Atzeni. 2020. "A Review of Heat Treatments on Improving the Quality and Residual Stresses of the Ti–6Al–4V Parts Produced by Additive Manufacturing." Metals 10, no. 8: 1006.
Additive manufacturing allows for a great degree of design freedom and is rapidly becoming a mainstream manufacturing process. However, as in all manufacturing processes, it has its limitations and specificities. Equipping engineers with this knowledge allows for a higher degree of optimization, extracting the most out of this technology. Therefore, a specific part design was devised and created via L-PBF (Laser Powder Bed Fusion) using AlSi10Mg powder. Certain parameters were varied to identify the influence on material density, hardness, roughness, residual stress and microstructures. It was found that on heat treated parts laser pattern strategy is one of the most influential aspects, showing that chessboard and stripes 67° improved outcome; average Ra roughness varied between 8–12 µm, residual stress was higher on vertical surfaces than horizontal surfaces, with the combination of support structures and stripes 67° strategies generating the lowest residual stress (205 MPa on a lateral/vertical face), hardness was non-orientation dependent and larger on samples with chessboard fabrication strategies, while microstructures were composed of α–Al dendrites surrounded by Si particles. The distribution and grain size of the microstructure is dependent on location regarding melt pool and HAZ area. Furthermore, Al–Mg oxides were encountered on the surface, along with pores generating from lack of fusion.
Ronny M. Gouveia; Francisco J. G. Silva; Eleonora Atzeni; Dušan Sormaz; Jorge Lino Alves; António Bastos Pereira. Effect of Scan Strategies and Use of Support Structures on Surface Quality and Hardness of L-PBF AlSi10Mg Parts. Materials 2020, 13, 2248 .
AMA StyleRonny M. Gouveia, Francisco J. G. Silva, Eleonora Atzeni, Dušan Sormaz, Jorge Lino Alves, António Bastos Pereira. Effect of Scan Strategies and Use of Support Structures on Surface Quality and Hardness of L-PBF AlSi10Mg Parts. Materials. 2020; 13 (10):2248.
Chicago/Turabian StyleRonny M. Gouveia; Francisco J. G. Silva; Eleonora Atzeni; Dušan Sormaz; Jorge Lino Alves; António Bastos Pereira. 2020. "Effect of Scan Strategies and Use of Support Structures on Surface Quality and Hardness of L-PBF AlSi10Mg Parts." Materials 13, no. 10: 2248.
Residual stresses (RS) of great magnitude are usually present in parts produced by Laser Powder Bed Fusion (PBF-LB), mainly owing to the extreme temperature gradients and high cooling rates involved in the process. Those “hidden” stresses can be detrimental to a part’s mechanical properties and fatigue life; therefore, it is crucial to know their magnitude and orientation. The hole-drilling strain-gage method was used to determine the RS magnitude and direction-depth profiles. Cuboid specimens in the as-built state, and after standard solution annealing and ageing heat treatment conditions, were prepared to study the RS evolution throughout the heat treatment stages. Measurements were performed on the top and lateral surfaces. In the as-built specimens, tensile stresses of ~400 MPa on the top and above 600 MPa on the lateral surface were obtained. On the lateral surface, RS anisotropy was noticed, with the horizontally aligned stresses being three times lower than the vertically aligned. RS decreased markedly after the first heat treatment. On heat-treated specimens, magnitude oscillations were observed. By microstructure analysis, the presence of carbides was verified, which is a probable root for the oscillations. Furthermore, compressive stresses immediate to the surface were obtained in heat-treated specimens, which is not in agreement with the typical characteristics of parts fabricated by PBF-LB, i.e., tensile stresses at the surface and compressive stresses in the part’s core.
Rafael Barros; Francisco J. G. Silva; Ronny M. Gouveia; Abdollah Saboori; Giulio Marchese; Sara Biamino; Alessandro Salmi; Eleonora Atzeni. Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment. Metals 2019, 9, 1290 .
AMA StyleRafael Barros, Francisco J. G. Silva, Ronny M. Gouveia, Abdollah Saboori, Giulio Marchese, Sara Biamino, Alessandro Salmi, Eleonora Atzeni. Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment. Metals. 2019; 9 (12):1290.
Chicago/Turabian StyleRafael Barros; Francisco J. G. Silva; Ronny M. Gouveia; Abdollah Saboori; Giulio Marchese; Sara Biamino; Alessandro Salmi; Eleonora Atzeni. 2019. "Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment." Metals 9, no. 12: 1290.
Directed Energy Deposition (DED) is one of the most promising additive manufacturing technologies for the production of large metal components and because of the possibility it offers of adding material to an existing part. Nevertheless, DED is considered premature for industrial production, because the identification of the process parameters may be a very complex task. An original hybrid analytic-numerical model, related to the physics of laser powder DED, is presented in this work in order to evaluate easily and quickly the effects of different sets of process parameters on track deposition outcomes. In the proposed model, the volume of the deposited material is modeled as a function of process parameters using a synergistic interaction between regression-based analytic models and a novel element activation strategy. The model is implemented in a Finite Element (FE) software, and the forecasting capability is assessed by comparing the numerical results with experimental data from the literature. The predicted results show a reasonable correlation with the experimental dimensions of the melt pool and demonstrate that the proposed model may be used for prediction purposes, if a specific set of process parameters that guarantees adequate adhesion of the deposited track to the substrate is introduced.
Gabriele Piscopo; Eleonora Atzeni; Alessandro Salmi. A Hybrid Modeling of the Physics-Driven Evolution of Material Addition and Track Generation in Laser Powder Directed Energy Deposition. Materials 2019, 12, 2819 .
AMA StyleGabriele Piscopo, Eleonora Atzeni, Alessandro Salmi. A Hybrid Modeling of the Physics-Driven Evolution of Material Addition and Track Generation in Laser Powder Directed Energy Deposition. Materials. 2019; 12 (17):2819.
Chicago/Turabian StyleGabriele Piscopo; Eleonora Atzeni; Alessandro Salmi. 2019. "A Hybrid Modeling of the Physics-Driven Evolution of Material Addition and Track Generation in Laser Powder Directed Energy Deposition." Materials 12, no. 17: 2819.
Alessandro Salmi; Eleonora Atzeni. Residual stress analysis of thin AlSi10Mg parts produced by Laser Powder Bed Fusion. Virtual and Physical Prototyping 2019, 15, 49 -61.
AMA StyleAlessandro Salmi, Eleonora Atzeni. Residual stress analysis of thin AlSi10Mg parts produced by Laser Powder Bed Fusion. Virtual and Physical Prototyping. 2019; 15 (1):49-61.
Chicago/Turabian StyleAlessandro Salmi; Eleonora Atzeni. 2019. "Residual stress analysis of thin AlSi10Mg parts produced by Laser Powder Bed Fusion." Virtual and Physical Prototyping 15, no. 1: 49-61.
Laser powder bed fusion (L-PBF) is an additive manufacturing (AM) process that allows to build full dense metal complex part. However, despite the obvious benefits of L-PBF process, it is affected by specific technological drawbacks and it suffers from issues regarding design support tools. In order to fully exploit the advantages of L-PBF, it is necessary to know the technological constraints, such as material availability and the need to minimise the support structures. In this paper, an integrated design procedure that involves topology optimisation, design for laser powder bed fusion rules and finishing requirements is presented in order to define practical guidelines for successful AM of metal parts. The procedure is tested using a case study to prove the effectiveness of the proposed approach.
Alessandro Salmi; Flaviana Calignano; Manuela Galati; Eleonora Atzeni. An integrated design methodology for components produced by laser powder bed fusion (L-PBF) process. Virtual and Physical Prototyping 2018, 13, 191 -202.
AMA StyleAlessandro Salmi, Flaviana Calignano, Manuela Galati, Eleonora Atzeni. An integrated design methodology for components produced by laser powder bed fusion (L-PBF) process. Virtual and Physical Prototyping. 2018; 13 (3):191-202.
Chicago/Turabian StyleAlessandro Salmi; Flaviana Calignano; Manuela Galati; Eleonora Atzeni. 2018. "An integrated design methodology for components produced by laser powder bed fusion (L-PBF) process." Virtual and Physical Prototyping 13, no. 3: 191-202.
This work explores the feasibility of using the Abrasive Fluidized Bed (AFB) method to finish flat AlSi10Mg substrates manufactured by Direct Metal Laser Sintering (DMLS). Finishing was performed by rotating the substrates inside a fluidized bed of abrasives at high speeds. The interaction between the fluidized abrasives and AlSi10Mg substrates has been investigated to analyze the influence of the operational parameters, namely, abrasive type and rotational speed, on the finishing performance. The morphological features of the substrates and geometrical tolerances have been inspected by field emission gun–scanning electron microscopy (FEG–SEM) and contact gauge profilometry. After short finishing cycles, the substrates featured a smoother surface morphology, while the edges were only influenced slightly by the abrasive impacts. Abrasive Fluidized Bed (AFB) can therefore be considered a potential easy-to-automate, low cost, low time consuming and sustainable finishing technology for metal parts obtained through additive manufacturing.
E. Atzeni; M. Barletta; Flaviana Calignano; L. Iuliano; Gianluca Rubino; V. Tagliaferri. Abrasive Fluidized Bed (AFB) finishing of AlSi10Mg substrates manufactured by Direct Metal Laser Sintering (DMLS). Additive Manufacturing 2016, 10, 15 -23.
AMA StyleE. Atzeni, M. Barletta, Flaviana Calignano, L. Iuliano, Gianluca Rubino, V. Tagliaferri. Abrasive Fluidized Bed (AFB) finishing of AlSi10Mg substrates manufactured by Direct Metal Laser Sintering (DMLS). Additive Manufacturing. 2016; 10 ():15-23.
Chicago/Turabian StyleE. Atzeni; M. Barletta; Flaviana Calignano; L. Iuliano; Gianluca Rubino; V. Tagliaferri. 2016. "Abrasive Fluidized Bed (AFB) finishing of AlSi10Mg substrates manufactured by Direct Metal Laser Sintering (DMLS)." Additive Manufacturing 10, no. : 15-23.
E. Atzeni; E. Bassoli; Lucia Denti; Andrea Gatto; L. Iuliano; Paolo Minetola; A. Salmi. Tolerance Analysis for Cast vs Machined Dental Implants. Procedia CIRP 2015, 33, 263 -268.
AMA StyleE. Atzeni, E. Bassoli, Lucia Denti, Andrea Gatto, L. Iuliano, Paolo Minetola, A. Salmi. Tolerance Analysis for Cast vs Machined Dental Implants. Procedia CIRP. 2015; 33 ():263-268.
Chicago/Turabian StyleE. Atzeni; E. Bassoli; Lucia Denti; Andrea Gatto; L. Iuliano; Paolo Minetola; A. Salmi. 2015. "Tolerance Analysis for Cast vs Machined Dental Implants." Procedia CIRP 33, no. : 263-268.
M Krishnan; E Atzeni; R Canali; Diego Manfredi; Flaviana Calignano; E Ambrosio; L Iuliano. Influence of post-processing operations on mechanical properties of AlSi 10Mg parts by DMLS. High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping 2013, 243 -248.
AMA StyleM Krishnan, E Atzeni, R Canali, Diego Manfredi, Flaviana Calignano, E Ambrosio, L Iuliano. Influence of post-processing operations on mechanical properties of AlSi 10Mg parts by DMLS. High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping. 2013; ():243-248.
Chicago/Turabian StyleM Krishnan; E Atzeni; R Canali; Diego Manfredi; Flaviana Calignano; E Ambrosio; L Iuliano. 2013. "Influence of post-processing operations on mechanical properties of AlSi 10Mg parts by DMLS." High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping , no. : 243-248.
E Atzeni; L Iuliano; G Marchiandi; Paolo Minetola; A Salmi; E Bassoli; Lucia Denti; Andrea Gatto. Additive manufacturing as a cost-effective way to produce metal parts. High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping 2013, 3 -8.
AMA StyleE Atzeni, L Iuliano, G Marchiandi, Paolo Minetola, A Salmi, E Bassoli, Lucia Denti, Andrea Gatto. Additive manufacturing as a cost-effective way to produce metal parts. High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping. 2013; ():3-8.
Chicago/Turabian StyleE Atzeni; L Iuliano; G Marchiandi; Paolo Minetola; A Salmi; E Bassoli; Lucia Denti; Andrea Gatto. 2013. "Additive manufacturing as a cost-effective way to produce metal parts." High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping , no. : 3-8.
Andrea Gatto; E Bassoli; Lucia Denti; E Atzeni; L Iuliano; G Marchiandi; Paolo Minetola; A Salmi; Flaviana Calignano. Electro-discharge drilling on DMLS parts in Co-Cr-Mo alloy. High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping 2013, 237 -242.
AMA StyleAndrea Gatto, E Bassoli, Lucia Denti, E Atzeni, L Iuliano, G Marchiandi, Paolo Minetola, A Salmi, Flaviana Calignano. Electro-discharge drilling on DMLS parts in Co-Cr-Mo alloy. High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping. 2013; ():237-242.
Chicago/Turabian StyleAndrea Gatto; E Bassoli; Lucia Denti; E Atzeni; L Iuliano; G Marchiandi; Paolo Minetola; A Salmi; Flaviana Calignano. 2013. "Electro-discharge drilling on DMLS parts in Co-Cr-Mo alloy." High Value Manufacturing: Advanced Research in Virtual and Rapid Prototyping , no. : 237-242.
In this paper, a characterization of an AlSiMg alloy processed by direct metal laser sintering (DMLS) is presented, from the analysis of the starting powders, in terms of size, morphology and chemical composition, through to the evaluation of mechanical and microstructural properties of specimens built along different orientations parallel and perpendicular to the powder deposition plane. With respect to a similar aluminum alloy as-fabricated, a higher yield strength of about 40% due to the very fine microstructure, closely related to the mechanisms involved in this additive process is observed.
Diego Manfredi; Flaviana Calignano; Manickavasagam Krishnan; Riccardo Canali; Elisa Paola Ambrosio; Eleonora Atzeni. From Powders to Dense Metal Parts: Characterization of a Commercial AlSiMg Alloy Processed through Direct Metal Laser Sintering. Materials 2013, 6, 856 -869.
AMA StyleDiego Manfredi, Flaviana Calignano, Manickavasagam Krishnan, Riccardo Canali, Elisa Paola Ambrosio, Eleonora Atzeni. From Powders to Dense Metal Parts: Characterization of a Commercial AlSiMg Alloy Processed through Direct Metal Laser Sintering. Materials. 2013; 6 (3):856-869.
Chicago/Turabian StyleDiego Manfredi; Flaviana Calignano; Manickavasagam Krishnan; Riccardo Canali; Elisa Paola Ambrosio; Eleonora Atzeni. 2013. "From Powders to Dense Metal Parts: Characterization of a Commercial AlSiMg Alloy Processed through Direct Metal Laser Sintering." Materials 6, no. 3: 856-869.
A Salmi; E Atzeni; L Iuliano. Application of time compression techniques to dental restoration. Innovative Developments in Virtual and Physical Prototyping 2011, 169 -176.
AMA StyleA Salmi, E Atzeni, L Iuliano. Application of time compression techniques to dental restoration. Innovative Developments in Virtual and Physical Prototyping. 2011; ():169-176.
Chicago/Turabian StyleA Salmi; E Atzeni; L Iuliano. 2011. "Application of time compression techniques to dental restoration." Innovative Developments in Virtual and Physical Prototyping , no. : 169-176.
New brake-pad materials are inhomogeneous compounds with a variety of metallic and ceramic phases, whose interaction with the tool during the grinding operation is not fully understood. Yet, ground surface quality strongly influences the bedding-in phase. This research surveys how grinding operation affects the pad surface. The purpose is pursued by adopting an investigation protocol merging macroscopic outcomes with the study of chip-removal mechanisms and of the ground surface morphology in the microscale. A specific set of grinding tests is carried out on the friction material under different kinematic conditions. Macroscopic indicators of the process performances are measured and modeled. At a closer look, the ground surface shows a complex morphology that cannot be completely described by roughness values, but depends on how the various phases are distributed in the material and how they are affected by the tool during abrasion. A multiscale inspection procedure is proposed to assess the performances of a machining operation on complex materials, where the descriptive power of standard technological tests becomes inadequate.
E. Bassoli; E. Atzeni; L. Iuliano. Grinding Micromechanisms of a Sintered Friction Material. Journal of Manufacturing Science and Engineering 2011, 133, 014501 .
AMA StyleE. Bassoli, E. Atzeni, L. Iuliano. Grinding Micromechanisms of a Sintered Friction Material. Journal of Manufacturing Science and Engineering. 2011; 133 (1):014501.
Chicago/Turabian StyleE. Bassoli; E. Atzeni; L. Iuliano. 2011. "Grinding Micromechanisms of a Sintered Friction Material." Journal of Manufacturing Science and Engineering 133, no. 1: 014501.
In recent years, digitizing and automation have gained an important role in manufacturing of dental devices. Instead of the traditional plaster model procedure, scanning techniques may be used for the geometry acquisition. Point clouds are processed and converted into standard CAD models, from which metal tooth cap can be fabricated by milling, integrating CAM tool, or by rapid manufacturing (RM) techniques. Good quality control is critical to ensure the crown fit: an improper fit could cause crown falling off. So far there is no standard procedure for evaluating quality of both 3D digitization and milling/RM cap making processes. Thus, a specific benchmark is designed to represent critical features of a stone replica, like a dental arch with studs resembling teeth prepared for crowns installation. The benchmark is then produced and measured by means of a coordinate measuring machin
Andrea Gatto; E Atzeni; L Iuliano; A Salmi; Paolo Minetola. A benchmark for accuracy evaluation of dental crowns up-to-date manufacturing. Innovative Developments in Design and Manufacturing 2009, 1 .
AMA StyleAndrea Gatto, E Atzeni, L Iuliano, A Salmi, Paolo Minetola. A benchmark for accuracy evaluation of dental crowns up-to-date manufacturing. Innovative Developments in Design and Manufacturing. 2009; ():1.
Chicago/Turabian StyleAndrea Gatto; E Atzeni; L Iuliano; A Salmi; Paolo Minetola. 2009. "A benchmark for accuracy evaluation of dental crowns up-to-date manufacturing." Innovative Developments in Design and Manufacturing , no. : 1.
A Gatto; E Atzeni; L Iuliano; A Salmi; P Minetola. Artificial teeth manufacturing. Innovative Developments in Design and Manufacturing 2009, 1 .
AMA StyleA Gatto, E Atzeni, L Iuliano, A Salmi, P Minetola. Artificial teeth manufacturing. Innovative Developments in Design and Manufacturing. 2009; ():1.
Chicago/Turabian StyleA Gatto; E Atzeni; L Iuliano; A Salmi; P Minetola. 2009. "Artificial teeth manufacturing." Innovative Developments in Design and Manufacturing , no. : 1.
The grinding of friction material brake pad, necessary to ensure a flat surface, generates the surface roughness which highly influences the friction coefficient. This paper deals with an experimental activity focused on the evaluation of the surface roughness after a grinding operation of an innovative sintered friction material. A regression analysis has been used to model the relationship among surface roughness and kinematic parameters. An instrumented tangential grinding machine controlled by a CNC system has been used in this activity. During the process the normal and tangential grinding forces have been measured by a force measurement device.
E. Atzeni; L. Iuliano. Experimental study on grinding of a sintered friction material. Journal of Materials Processing Technology 2008, 196, 184 -189.
AMA StyleE. Atzeni, L. Iuliano. Experimental study on grinding of a sintered friction material. Journal of Materials Processing Technology. 2008; 196 (1-3):184-189.
Chicago/Turabian StyleE. Atzeni; L. Iuliano. 2008. "Experimental study on grinding of a sintered friction material." Journal of Materials Processing Technology 196, no. 1-3: 184-189.