Microstructure of Built Part Obtained by Powder Bed Fusion Process with Metal

2019 ◽  
Vol 825 ◽  
pp. 1-6
Author(s):  
Tatsuaki Furumoto ◽  
Kyota Egashira ◽  
Souta Matsuura ◽  
Makoto Nikawa ◽  
Masato Okada ◽  
...  

The influence of various process parameters on the building of maraging steel powder by the selective laser melting (SLM) processes is investigated. The microstructure in the built part was observed and the influence of the heat treatment was evaluated. As results, the depth of solidified layer was higher than that of deposited metal powder, and its value was influenced with the process parameters. The microstructure in the boundary between the built part and the substrate was quite different from the built part even if the suitable heat treatment was performed.

2019 ◽  
Vol 818 ◽  
pp. 72-76 ◽  
Author(s):  
Konda Gokuldoss Prashanth ◽  
Sergio Scudino

Laser based powder bed fusion (LBPF) or selective laser melting (SLM) is making a leap march towards fabricating novel materials with improved functionalities. An attempt has been made here to fabricate hard quasicrystalline composites via SLM, which demonstrates that the process parameters can be used to vary the phases in the composites. The mechanical properties of the composite depend on their constituents and hence can be varied by varying the process parameters. The results show that SLM not only produces parts with improved functionalities and complex shape but also leads to defined phases and tunable properties.


Procedia CIRP ◽  
2020 ◽  
Vol 94 ◽  
pp. 167-172
Author(s):  
Max Horn ◽  
Lukas Langer ◽  
Mario Schafnitzel ◽  
Simone Dietrich ◽  
Georg Schlick ◽  
...  

2021 ◽  
Vol 27 (3) ◽  
pp. 122-126
Author(s):  
Giulia Stornelli ◽  
Damiano Gaggia ◽  
Marco Rallini ◽  
Andrea Di Schino

Laser Powder Bed Fusion (L-PBF) is a widespread additive manufacturing technology in industrial applications, for metal components manufacturing. Maraging steel is a special class of Fe-Ni alloys, typically used in the aerospace and tooling sectors due to their good combination of mechanical strength and toughness. This work analyses the heat treatment effect on the microstructure and hardness value of 300-grade maraging steel manufactured by the L-PBF process. The considered heat treatment consists of a solution annealing treatment followed by quenching and ageing hardening treatment. The effect of ageing temperature is reported, in a wide temperature range. Results show that solution annealing treatment fully dissolves the solidification structure caused by the L-PBF process. Moreover, the ageing hardening treatment has a significant impact on the hardness, hence on strength, of L-PBF maraging steel. The optimal ageing conditions for the L-PBF maraging steel are identified and reported: in particular, results show that the hardness of 583 HV is achieved following ageing treatment at 490 °C for 6 hours. A higher treatment temperature leads to over-ageing resulting in a decrease of hardness. Conversely, an excessive ageing time does not seem to affect the hardness value, for the ageing temperature of 490 °C.


Author(s):  
Shukri Afazov ◽  
Adam Roberts ◽  
Louise Wright ◽  
Prashant Jadhav ◽  
Adam Holloway ◽  
...  

AbstractMetal powder bed fusion (MPBF) is not a standalone process, and other manufacturing technologies, such as heat treatment and surface finishing operations, are often required to achieve a high-quality component. To optimise each individual process for a given component, its progression through the full process chain must be considered and understood, which can be achieved through the use of validated models. This article aims to provide an overview of the various modelling techniques that can be utilised in the development of a digital twin for MPBF process chains, including methods for data transfer between physical and digital entities and uncertainty evaluation. An assessment of the current maturity of modelling techniques through the use of technology readiness levels is conducted to understand their maturity. Summary remarks highlighting the advantages and disadvantages in physics-based modelling techniques used in MPBF research domains  (i.e. prediction of: powder distortion; temperature; material properties; distortion; residual stresses; as well as topology optimisation), post-processing (i.e. modelling of: machining; heat treatment; and surface engineering), and digital twins (i.e. simulation of manufacturing process chains; interoperability; and computational performance) are provided. Future perspectives for the challenges in these MPBF research domains are also discussed and summarised.


Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 538 ◽  
Author(s):  
Fabrizia Caiazzo ◽  
Vittorio Alfieri ◽  
Giuseppe Casalino

Laser powder bed fusion (LPBF) can fabricate products with tailored mechanical and surface properties. In fact, surface texture, roughness, pore size, the resulting fractional density, and microhardness highly depend on the processing conditions, which are very difficult to deal with. Therefore, this paper aims at investigating the relevance of the volumetric energy density (VED) that is a concise index of some governing factors with a potential operational use. This paper proves the fact that the observed experimental variation in the surface roughness, number and size of pores, the fractional density, and Vickers hardness can be explained in terms of VED that can help the investigator in dealing with several process parameters at once.


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 796
Author(s):  
Aya Takase ◽  
Takuya Ishimoto ◽  
Naotaka Morita ◽  
Naoko Ikeo ◽  
Takayoshi Nakano

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.


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