scholarly journals Effect of processing parameters on the densification, microstructure and crystallographic texture during the laser powder bed fusion of pure tungsten

Author(s):  
A.T. Sidambe ◽  
Y. Tian ◽  
P.B. Prangnell ◽  
P. Fox
2022 ◽  
Vol 206 ◽  
pp. 114252
Author(s):  
Tsubasa Todo ◽  
Takuya Ishimoto ◽  
Ozkan Gokcekaya ◽  
Jongyeong Oh ◽  
Takayoshi Nakano

Author(s):  
Rafael de Moura Nobre ◽  
Willy Ank de Morais ◽  
Matheus Tavares Vasques ◽  
Jhoan Guzmán ◽  
Daniel Luiz Rodrigues Junior ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4879
Author(s):  
Mireia Vilanova ◽  
Rubén Escribano-García ◽  
Teresa Guraya ◽  
Maria San Sebastian

A method to find the optimum process parameters for manufacturing nickel-based superalloy Inconel 738LC by laser powder bed fusion (LPBF) technology is presented. This material is known to form cracks during its processing by LPBF technology; thus, process parameters have to be optimized to get a high quality product. In this work, the objective of the optimization was to obtain samples with fewer pores and cracks. A design of experiments (DoE) technique was implemented to define the reduced set of samples. Each sample was manufactured by LPBF with a specific combination of laser power, laser scan speed, hatch distance and scan strategy parameters. Using the porosity and crack density results obtained from the DoE samples, quadratic models were fitted, which allowed identifying the optimal working point by applying the response surface method (RSM). Finally, five samples with the predicted optimal processing parameters were fabricated. The examination of these samples showed that it was possible to manufacture IN738LC samples free of cracks and with a porosity percentage below 0.1%. Therefore, it was demonstrated that RSM is suitable for obtaining optimum process parameters for IN738LC alloy manufacturing by LPBF technology.


Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1273 ◽  
Author(s):  
Barry Mooney ◽  
Kyriakos Kourousis

Maraging steel is an engineering alloy which has been widely employed in metal additive manufacturing. This paper examines manufacturing and post-processing factors affecting the properties of maraging steel fabricated via laser powder bed fusion (L-PBF). It covers the review of published research findings on how powder quality feedstock, processing parameters, laser scan strategy, build orientation and heat treatment can influence the microstructure, density and porosity, defects and residual stresses developed on L-PBF maraging steel, with a focus on the maraging steel 300 alloy. This review offers an evaluation of the resulting mechanical properties of the as-built and heat-treated maraging steel 300, with a focus on anisotropic characteristics. Possible directions for further research are also identified.


Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1064
Author(s):  
Shinya Hibino ◽  
Tsubasa Todo ◽  
Takuya Ishimoto ◽  
Ozkan Gokcekaya ◽  
Yuichiro Koizumi ◽  
...  

The influence of various laser powder bed fusion (LPBF) process parameters on the crystallographic textures and mechanical properties of a typical Ni-based solid-solution strengthened alloy, Hastelloy-X, was examined. Samples were classified into four groups based on the type of crystallographic texture: single crystalline-like microstructure with <100>//build direction (BD) (<100>-SCM), single crystalline-like microstructure with <110>//BD (<110>-SCM), crystallographic lamellar microstructure (CLM), or polycrystalline microstructure (PCM). These four crystallographic textures were realized in Hastelloy-X for the first time here to the best of our knowledge. The mechanical properties of the samples varied depending on their texture. The tensile properties were affected not only by the Schmid factor but also by the grain size and the presence of lamellar boundaries (grain boundaries). The lamellar boundaries at the interface between the <110>//BD oriented main layers and the <100>//BD-oriented sub-layers of CLM contributed to the resistance to slip transmission and the increased proof stress. It was possible to control a wide range of crystallographic microstructures via the LPBF process parameters, which determines the melt pool morphology and solidification behavior.


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