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2022 ◽  
Vol 34 (1) ◽  
pp. 012016
Author(s):  
Jyi Sheuan Jason Ten ◽  
Fern Lan Ng ◽  
Hang Li Seet ◽  
Mui Ling Sharon Nai

Author(s):  
Kirstin Riener ◽  
Tino Pfalz ◽  
Florian Funcke ◽  
Gerhard Leichtfried

AbstractThe growing demand for more materials available for the LPBF-process, in particular high-strength aluminum alloys, is evident in the market. In the present work, a systematic investigation of the processability of aluminum 6182 series alloys, using LPBF, was carried out. For this purpose, the influence of process parameters, especially of enhanced preheating by heating the substrate plate during the LPBF process, on the microstructure of EN AW 6182 specimens was studied.Experiments were conducted at different preheating temperatures always using the same d-optimal design-of-experiments, the laser power, scanning speed, hatch distance, and laser focus position being varied over a wide range.It was found that the preheating temperature has the strongest impact on hot cracking. Higher temperatures result in a significantly reduced number of hot cracks in the microstructure. Moreover, an equiaxed microstructure of the specimens manufactured can be observed at preheating temperatures of 500 °C. In addition to the preheating temperature, the achievable part density is most strongly affected by the laser focus position and the laser power, whereas the hatch distance shows no discernible impact on the part density. Furthermore, neither the hatch distance nor the laser focus position shows any significant effect on hot cracking.In combination with the optimal scanning parameters, crack-free parts with a fully equiaxed grain structure and densities > 99.0% can be manufactured via LPBF at a preheating temperature of 500 °C.


Author(s):  
R. Tosi ◽  
E. Muzangaza ◽  
X. P. Tan ◽  
D. Wimpenny ◽  
M. M. Attallah

AbstractProcessing, microstructure, and mechanical properties of the hybrid electron beam powder bed fusion (E-PBF) additive manufacturing of Ti–6Al–4V have been investigated. We explore the possibility of integrating the substrate as a part of the final component as a repair, integrated, or consolidated part. Various starting plate surface conditions are used to understand the joining behavior and their microstructural properties in the bonding region between the plate and initial deposited layers. It is found that mechanical failures mainly occur within the substrate region due to the dominant plastic strains localized in the weaker Ti–6Al–4V substrate. The hybrid concept is successfully proven with satisfactory bonding performance between the E-PBF build and substrate. This investigation improves the practice of using the hybrid E-PBF additive manufacturing technique and provides basic understanding to this approach.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 572
Author(s):  
Constantin Böhm ◽  
Martin Werz ◽  
Stefan Weihe

The range of available aluminum alloy powders for laser powder bed fusion (LPBF) is restricted to mainly Al–Si based alloys. Currently aluminum alloy powders, designed for lightweight application, based on Al–Mg (5000 series), Al–Si–Mg (6000 series), or Al–Zn–Mg (7000 series), cannot be processed by LPBF without solidification cracks. This has an impact on the potential of LPBF for lightweight applications. In fusion welding, solidification cracks are eliminated by using filler materials. This study aims to transfer the known procedure to LPBF, by supplementing EN AW-5083 (AlMg4.5Mn0.7) with AlSi10Mg. EN AW-5083 and two modifications (+7 wt.% and +15 wt.% AlSi10Mg) were produced by LPBF and analyzed. It was found that, in EN AW-5083, the solidification cracks have a length ≥200 µm parallel to the building direction. Furthermore, the solidification cracks can already be eliminated by supplementing 7 wt.% AlSi10Mg. The microstructure analysis revealed that, by supplementing AlSi10Mg, the melt pool boundaries become visible, and the grain refines by 40% relative to the base alloy. Therefore, adding a low melting point phase and grain refinement are the mechanisms that eliminate solidification cracking. This study illustrates a practical approach to eliminate solidification cracks in LPBF.


2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Chia-Hung Hung ◽  
Tunay Turk ◽  
M. Hossein Sehhat ◽  
Ming C. Leu

Purpose This paper aims to present the development and experimental study of a fully automated system using a novel laser additive manufacturing technology called laser foil printing (LFP), to fabricate metal parts layer by layer. The mechanical properties of parts fabricated with this novel system are compared with those of comparable methodologies to emphasize the suitability of this process. Design/methodology/approach Test specimens and parts with different geometries were fabricated from 304L stainless steel foil using an automated LFP system. The dimensions of the fabricated parts were measured, and the mechanical properties of the test specimens were characterized in terms of mechanical strength and elongation. Findings The properties of parts fabricated with the automated LFP system were compared with those of parts fabricated with the powder bed fusion additive manufacturing methods. The mechanical strength is higher than those of parts fabricated by the laser powder bed fusion and directed energy deposition technologies. Originality/value To the best knowledge of authors, this is the first time a fully automated LFP system has been developed and the properties of its fabricated parts were compared with other additive manufacturing methods for evaluation.


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