scholarly journals Material Characterisation and Computational Thermal Modelling of Electron Beam Powder Bed Fusion Additive Manufacturing of Ti2448 Titanium Alloy

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7359
Author(s):  
Qiushuang Wang ◽  
Wenyou Zhang ◽  
Shujun Li ◽  
Mingming Tong ◽  
Wentao Hou ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Thermal History ◽  
Computational Modelling ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Material Microstructure ◽  
Powder Bed ◽  
Β Phase ◽  
Α Phase

Ti-24Nb-4Zr-8Sn (Ti2448) is a metastable b-type titanium alloy developed for biomedical applications. In this work, cylindrical samples of Ti2448 alloy have been successfully manufactured by using the electron beam powder bed fusion (PBF-EB) technique. The thermal history and microstructure of manufactured samples are characterised using computational and experimental methods. To analyse the influence of thermal history on the microstructure of materials, the thermal process of PBF-EB has been computationally predicted using the layer-by-layer modelling method. The microstructure of the Ti2448 alloy mainly includes β phase and a small amount of α” phase. By comparing the experimental results of material microstructure with the computational modelling results of material thermal history, it can be seen that aging time and aging temperature lead to the variation of α” phase content in manufactured samples. The computational modelling proves to be an effective tool that can help experimentalists to understand the influence of macroscopic processes on material microstructural evolution and hence potentially optimise the process parameters of PBF-EB to eliminate or otherwise modify such microstructural gradients.

scholarly journals Comparison of Phase Characteristics and Residual Stresses in Ti-6Al-4V Alloy Manufactured by Laser Powder Bed Fusion (L-PBF) and Electron Beam Powder Bed Fusion (EB-PBF) Techniques

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 796
Author(s):  
Aya Takase ◽  
Takuya Ishimoto ◽  
Naotaka Morita ◽  
Naoko Ikeo ◽  
Takayoshi Nakano
Keyword(s):  
Electron Beam ◽  
Residual Stresses ◽  
Cooling Rate ◽  
Process Parameters ◽  
Phase Evolution ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Solidification Temperature ◽  
Powder Bed ◽  
Β Phase

Ti-6Al-4V alloy fabricated by laser powder bed fusion (L-PBF) and electron beam powder bed fusion (EB-PBF) techniques have been studied for applications ranging from medicine to aviation. The fabrication technique is often selected based on the part size and fabrication speed, while less attention is paid to the differences in the physicochemical properties. Especially, the relationship between the evolution of α, α’, and β phases in as-grown parts and the fabrication techniques is unclear. This work systematically and quantitatively investigates how L-PBF and EB-PBF and their process parameters affect the phase evolution of Ti-6Al-4V and residual stresses in the final parts. This is the first report demonstrating the correlations among measured parameters, indicating the lattice strain reduces, and c/a increases, shifting from an α’ to α+β or α structure as the crystallite size of the α or α’ phase increases. The experimental results combined with heat-transfer simulation indicate the cooling rate near the β transus temperature dictates the resulting phase characteristics, whereas the residual stress depends on the cooling rate immediately below the solidification temperature. This study provides new insights into the previously unknown differences in the α, α’, and β phase evolution between L-PBF and EB-PBF and their process parameters.

scholarly journals On the Impact of Build Envelope Sizes on E-PBF Processed Pure Iron

2021 ◽  
Author(s):  
C. J. J. Torrent ◽  
P. Krooß ◽  
T. Niendorf
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Thermal History ◽  
Powder Bed Fusion ◽  
Parameter Setting ◽  
Powder Bed ◽  
History Of ◽  
Specific Temperature ◽  
The Impact

AbstractIn additive manufacturing, the thermal history of a part determines its final microstructural and mechanical properties. The factors leading to a specific temperature profile are diverse. For the integrity of a parameter setting established, periphery variations must also be considered. In the present study, iron was processed by electron beam powder bed fusion. Parts realized by two process runs featuring different build plate sizes were analyzed. It is shown that the process temperature differs significantly, eventually affecting the properties of the processed parts.

scholarly journals On the in situ elimination of pores during laser powder bed fusion of a titanium alloy

2021 ◽  
Author(s):  
ling zhang ◽  
Wenhe Liao ◽  
Tingting Liu ◽  
Huiliang Wei ◽  
Changchun Zhang
Keyword(s):  
Titanium Alloy ◽  
Real Time ◽  
Laser Power ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed ◽  
Printing Quality ◽  
High Laser

Abstract The printing quality of the laser powder bed fusion (LPBF) components largely depends on the presence of various defects such as massive porosity. Thus, the efficient elimination of pores is an important factor to the production of a sound LPBF product. In this work, the efficacy of two in situ laser remelting approaches on the elimination of pores during LPBF of a titanium alloy Ti-6.5Al-3.5Mo-l.5Zr-0.3Si (TC11) were assessed using both experimental and computational methods. These two remelting methods are the surface remelting, and the layer-by-layer printing and remelting. A multi-track and multi-layer phenomenological model was established to compute the evolution of pores with the temperature and velocity fields. The results showed that surface remelting with a high laser power such as 180 W laser can effectively eliminate pores within three deposited layers. However, such a remelting cannot reach defects in deeper regions. Alternatively, the layer-by-layer remelting with a laser power of 180 W can effectively eliminate the pores formed in the previous layer in real time. The results obtained from this work can provide useful guidance for the in situ control of printing defects supported by the real time monitoring, feedback and operation systems of the intelligent LPBF equipment.

scholarly journals Sintered powder oxidation variation as a function of build height for titanium alloy produced by electron beam powder-bed fusion

2021 ◽  
pp. 100023
Author(s):  
Nicholas Derimow ◽  
Alejandro Romero ◽  
Aldo Rubio ◽  
Cesar Terrazas ◽  
Francisco Medina ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Electron Beam ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Sintered Powder

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

scholarly journals Influence of Microstructure and Defects on Mechanical Properties of AISI H13 Manufactured by Electron Beam Powder Bed Fusion

2021 ◽  
Author(s):  
Moritz Kahlert ◽  
Florian Brenne ◽  
Malte Vollmer ◽  
Thomas Niendorf
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Internal Cooling ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Cooling Channels ◽  
Fine Grained ◽  
Aisi H13

AbstractElectron beam powder bed fusion (E-PBF) is a well-known additive manufacturing process. Components are realized based on layer-by-layer melting of metal powder. Due to the high degree of design freedom, additive manufacturing came into focus of tooling industry, especially for tools with sophisticated internal cooling channels. The present work focuses on the relationships between processing, microstructure evolution, chemical composition and mechanical properties of a high alloyed tool steel AISI H13 (1.2344, X40CrMoV5-1) processed by E-PBF. The specimens are free of cracks, however, lack of fusion defects are found upon use of non-optimized parameters finally affecting the mechanical properties detrimentally. Specimens built based on suitable parameters show a relatively fine grained bainitic/martensitic microstructure, finally resulting in a high ultimate strength and an even slightly higher failure strain compared to conventionally processed and heat treated AISI H13.

scholarly journals 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 (7) ◽  
pp. 3429-3439 ◽  
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

Microstructure Appearance of TC4 Titanium Alloy Welded Join by Pulsed Electron Beam

2020 ◽  
Vol 982 ◽  
pp. 143-150
Author(s):  
Hai Lin Dai ◽  
Rui Zhao Du ◽  
Yun He ◽  
Shuai Xing ◽  
Fang Jun Liu
Keyword(s):  
Grain Size ◽  
Titanium Alloy ◽  
Electron Beam ◽  
Weld Metal ◽  
Pulsed Electron Beam ◽  
Tc4 Titanium Alloy ◽  
Β Phase ◽  
Α Phase ◽  
Fast Cooling ◽  
Cooling Velocity

Study on microstructure appearance of 3 mm thick TC4 titanium alloy welded join by common electron beam and pulsed electron beam were carried out. Experimental results show that pulsed electron beam improved grain size and decreased the cooling velocity of weld metal by oscillation and fast cooling effect, the acicular martensite decomposes β phase and transforms to finer and more α′ phase, which shows an interwoven pattern.

Grain Morphology and Texture Development in a Co-Cr-Mo Alloy Fabricated by Powder Bed Fusion with an Electron Beam

2019 ◽  
Author(s):  
Yufan Zhao ◽  
Yuichiro Koizumi ◽  
Kenta Aoyagi ◽  
Daixiu Wei ◽  
Kenta Yamanaka ◽  
...  
Keyword(s):  
Electron Beam ◽  
Grain Morphology ◽  
Texture Development ◽  
Powder Bed Fusion ◽  
Powder Bed
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