scholarly journals Numerical Investigation into the Effect of Different Parameters on the Geometrical Precision in the Laser-Based Powder Bed Fusion Process Chain

2020 ◽  
Vol 10 (10) ◽  
pp. 3414
Author(s):  
David De Baere ◽  
Mandanà Moshiri ◽  
Sankhya Mohanty ◽  
Guido Tosello ◽  
Jesper Henri Hattel
Keyword(s):  
Heat Treatment ◽  
Stress Relaxation ◽  
Heat Treatment Temperature ◽  
Base Plate ◽  
Treatment Temperature ◽  
Chain Model ◽  
Powder Bed Fusion ◽  
Process Chain ◽  
Post Processing ◽  
Powder Bed

Due to the layer-by-layer nature of the process, parts produced by laser-based powder bed fusion (LPBF) have high residual stresses, causing excessive deformations. To avoid this, parts are often post-processed by subjecting them to specially designed heat treatment cycles before or after their removal from the base plate. In order to investigate the effects of the choice of post-processing steps, in this work the entire LPBF process chain is modelled in a commercial software package. The developed model illustrates the possibilities of implementing and tailoring the process chain model for metal additive manufacturing using a general purpose finite element (FE) solver. The provided simplified computational example presents an idealised model to analyse the validity of implementing the LPBF process chain in FE software. The model is used to evaluate the effect of the order of the process chain, the heat treatment temperature and the duration of the heat treatment. The results show that the model is capable of qualitatively capturing the effect of the stress relaxation that occurs during a heat treatment at elevated temperature. Due to its implementation, the model is relatively insensitive to duration and heat treatment temperature, at least as long as it is above the relaxation temperature. Furthermore, the simulations suggest that, when post-processing, it is necessary to perform the stress relaxation before the part is removed from the base plate, in order to avoid a significant increase of the deformation. The paper demonstrates the capability of the simulation tool to evaluate the effects of variations in the process chain steps and highlights its potential usage in directing decision-making for LPBF process chain design.

scholarly journals A Novel γ′-Strengthened Nickel-Based Superalloy for Laser Powder Bed Fusion

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4930
Author(s):  
Jinghao Xu ◽  
Hans Gruber ◽  
Ru Lin Peng ◽  
Johan Moverare
Keyword(s):  
Heat Treatment ◽  
Additive Manufacturing ◽  
Solution Heat Treatment ◽  
Aging Treatment ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Post Processing ◽  
Powder Bed ◽  
Nickel Based Superalloy ◽  
Annealing Twins

An experimental printable γ′-strengthened nickel-based superalloy, MAD542, is proposed. By process optimization, a crack-free component with less than 0.06% defect was achieved by laser powder bed fusion (LPBF). After post-processing by solution heat treatment, a recrystallized structure was revealed, which was also associated with the formation of annealing twins. After the aging treatment, 60–65% γ′ precipitates were obtained with a cuboidal morphology. The success of printing and post-processing the new MAD542 superalloy may give new insights into alloy design approaches for additive manufacturing.

Effects of Heat Treatment Temperature on Photocatalytic Activity of TiO2/SiO2 Composite Aerogels

2013 ◽  
Vol 27 (10) ◽  
pp. 1079-1083
Author(s):  
Zhao-Hui LIU ◽  
Gen-Liang HOU ◽  
Xun-Jia SU ◽  
Feng GUO ◽  
Zhou XIAO ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Composite Aerogels

scholarly journals Review on additive hybrid- and multi-material-manufacturing of metals by powder bed fusion: state of technology and development potential

2021 ◽  
Author(s):  
M. Schneck ◽  
M. Horn ◽  
M. Schmitt ◽  
C. Seidel ◽  
G. Schlick ◽  
...  
Keyword(s):  
Review Paper ◽  
Powder Bed Fusion ◽  
Process Chain ◽  
Data Preparation ◽  
Powder Bed ◽  
Theoretical Approaches ◽  
Powder Deposition ◽  
Readiness Level ◽  
Manufacturing Readiness ◽  
2D And 3D

AbstractIn this review paper, the authors investigate the state of technology for hybrid- and multi-material (MM) manufacturing of metals utilizing additive manufacturing, in particular powder bed fusion processes. The study consists of three parts, covering the material combinations, the MM deposition devices, and the implications in the process chain. The material analysis is clustered into 2D- and 3D-MM approaches. Based on the reviewed literature, the most utilized material combination is steel-copper, followed by fusing dissimilar steels. Second, the MM deposition devices are categorized into holohedral, nozzle-based as well as masked deposition concepts, and compared in terms of powder deposition rate, resolution, and manufacturing readiness level (MRL). As a third aspect, the implications in the process chain are investigated. Therefore, the design of MM parts and the data preparation for the production process are analyzed. Moreover, aspects for the reuse of powder and finalization of MM parts are discussed. Considering the design of MM parts, there are theoretical approaches, but specific parameter studies or use cases are not present in the literature. Principles for powder separation are identified for exemplary material combinations, but results for further finalization steps of MM parts have not been found. In conclusion, 3D-MM manufacturing has a MRL of 4–5, which indicates that the technology can be produced in a laboratory environment. According to this maturity, several aspects for serial MM parts need to be developed, but the potential of the technology has been demonstrated. Thus, the next important step is to identify lead applications, which benefit from MM manufacturing and hence foster the industrialization of these processes.

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