scholarly journals The Effect of Post-Processing on the Mechanical Behavior of Ti6Al4V Manufactured by Electron Beam Powder Bed Fusion for General Aviation Primary Structural Applications

Aerospace ◽  
2020 ◽  
Vol 7 (6) ◽  
pp. 75
Author(s):  
Carmine Pirozzi ◽  
Stefania Franchitti ◽  
Rosario Borrelli ◽  
Antonio Chiariello ◽  
Luigi Di Palma
Keyword(s):  
Electron Beam ◽  
Mechanical Behavior ◽  
Electron Beam Melting ◽  
Melting Process ◽  
General Aviation ◽  
Powder Bed Fusion ◽  
Structural Elements ◽  
Post Processing ◽  
Powder Bed ◽  
Structural Applications

In this work a mechanical characterization of Ti6Al4V processed by electron beam powder bed fusion additive manufacturing was carried out to investigate the viability of this technology for the manufacturing of flyable parts for general aviation aircraft. Tests were performed on different manufacturing conditions in order to investigate the effect of post processing as machining on the mechanical behavior. The study provides useful information to airframe designers and manufacturing specialists that work with this technology. The investigation confirms the low process variability and provides data to be used in the design loop of general aviation primary structural elements. The test results show a high level of repeatability indicating that the process is well controlled and reliable enough to match the airworthiness requirements. In addition, the so-called “as-built specimens”, i.e., specimens produced by the electron beam melting machine without any major post-processing, have lower mechanical performances than specimens subjected to a machining phase after the electron beam melting process. Specific primary structural elements will be designed and flight cleared, resulting from the findings presented herein.

scholarly journals Electron Beam Melting of Niobium Alloys from Blended Powders

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5536
Author(s):  
Jameson P. Hankwitz ◽  
Christopher Ledford ◽  
Christopher Rock ◽  
Scott O’Dell ◽  
Timothy J. Horn
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Room Temperature ◽  
Powder Bed Fusion ◽  
Post Processing ◽  
Niobium Alloys ◽  
Powder Bed ◽  
Tungsten Alloys ◽  
Room Temperature Ductility ◽  
Structural Applications

Niobium-based tungsten alloys are desirable for high-temperature structural applications yet are restricted in practice by limited room-temperature ductility and fabricability. Powder bed fusion additive manufacturing is one technology that could be leveraged to process alloys with limited ductility, without the need for pre-alloying. A custom electron beam powder bed fusion machine was used to demonstrate the processability of blended Nb-1Zr, Nb-10W-1Zr-0.1C, and Nb-20W-1Zr-0.1C powders, with resulting solid optical densities of 99+%. Ultimately, post-processing heat treatments were required to increase tungsten diffusion in niobium, as well as to attain satisfactory mechanical properties.

scholarly journals In Situ Monitoring of Powder Bed Fusion Homogeneity in Electron Beam Melting

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7015
Author(s):  
Marco Grasso
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Infrared Imaging ◽  
Melting Process ◽  
In Situ Monitoring ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
In Situ Sensing ◽  
In Situ Detection

Increasing attention has been devoted in recent years to in situ sensing and monitoring of the electron beam melting process, ranging from seminal methods based on infrared imaging to novel methods based on backscattered electron detection. However, the range of available in situ monitoring capabilities and solutions is still quite limited compared to the wide number of studies and industrial toolkits in laser-based additive manufacturing processes. Some methods that are already industrially available in laser powder bed fusion systems, such as in situ detection of recoating errors, have not yet been investigated and tested in electron beam melting. Motivated by the attempt to fill this gap, we present a novel in situ monitoring methodology that can be easily implemented in industrial electron beam melting machines. The method is aimed at identifying local inhomogeneity and irregularities in the powder bed by means of layerwise image acquisition and processing, with no external illumination source apart from the light emitted by the hot material underneath the currently recoated layer. The results show that the proposed approach is suitable to detect powder bed anomalies, while also highlighting the link between the severity of in situ detected errors and the severity of resulting defects in the additively manufactured part.

scholarly journals Smoke Suppression in Electron Beam Melting of Inconel 718 Alloy Powder Based on Insulator–Metal Transition of Surface Oxide Film by Mechanical Stimulation

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4662
Author(s):  
Akihiko Chiba ◽  
Yohei Daino ◽  
Kenta Aoyagi ◽  
Kenta Yamanaka
Keyword(s):  
Electron Beam ◽  
Oxide Film ◽  
Ball Milling ◽  
Mechanical Stimulation ◽  
Electron Beam Melting ◽  
Alloy Powder ◽  
Powder Bed Fusion ◽  
Surface Oxide Film ◽  
Inconel 718 Alloy ◽  
Powder Bed

In powder bed fusion–electron beam melting, the alloy powder can scatter under electron beam irradiation. When this phenomenon—known as smoking—occurs, it makes the PBF-EBM process almost impossible. Therefore, avoiding smoking in EBM is an important research issue. In this study, we aimed to clarify the effects of powder bed preheating and mechanical stimulation on the suppression of smoking in the powder bed fusion–electron beam melting process. Direct current electrical resistivity and alternating current impedance spectroscopy measurements were conducted on Inconel 718 alloy powder at room temperature and elevated temperatures before and after mechanical stimulation (ball milling for 10–60 min) to investigate changes in the electrical properties of the surface oxide film, alongside X-ray photoelectron spectroscopy to identify the surface chemical composition. Smoking tests confirmed that preheating and ball milling both suppressed smoking. Furthermore, smoking did not occur after ball milling, even when the powder bed was not preheated. This is because the oxide film undergoes a dielectric–metallic transition due to the lattice strain introduced by ball milling. Our results are expected to benefit the development of the powder bed fusion–electron beam melting processes from the perspective of materials technology and optimization of the process conditions and powder properties to suppress smoking.

Correction to: Post-processing to Modify the α Phase Micro-Texture and β Phase Grain Morphology in Ti-6Al-4V Fabricated by Powder Bed Electron Beam Melting

2019 ◽  
Vol 50 (8) ◽  
pp. 3973-3974
Author(s):  
Peeyush Nandwana ◽  
Yousub Lee ◽  
Chasen Ranger ◽  
Anthony D. Rollett ◽  
Ryan R. Dehoff ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Grain Morphology ◽  
Post Processing ◽  
Powder Bed ◽  
Β Phase ◽  
Α Phase

Indentation-derived mechanical properties of Ti-6Al-4V: laser-powder bed fusion versus electron beam melting

2021 ◽  
pp. 130273
Author(s):  
Amir Hadadzadeh ◽  
Ebrahim Asadi ◽  
Shawkat Imam Shakil ◽  
Babak Shalchi Amirkhiz ◽  
Mohsen Mohammadi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Electron Beam Melting ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed
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