Abstract
In this paper, we have studied an additively manufactured metallic component, intended for ultra-high vacuum application, the exit-snout of the MACHINA transportable proton accelerator beam-line. Metal additive manufacturing components can exhibit heterogeneous and anisotropic microstructures. Two non-destructive imaging techniques, X-ray computed tomography and Neutron Tomography, were employed to examine its microstructure. They unveiled the presence of porosity and channels, the size and composition of grains and intergranular precipitates, and the general behavior of the spatial distribution of the solidification lines. While X-ray computed tomography evidenced qualitative details about the surface roughness and internal defects, neutron tomography showed excellent ability in imaging the spatial density distribution within the component. The anisotropy of the density was attributed to the material building orientation during the 3D printing process. Density variations suggest the possibility of defect pathways, which could affect high vacuum performances. In addition, these results highlight the importance of considering building orientation in the design for additive manufacturing for UHV applications.Graphical
Highlights
Additive manufacturing (AM) (Ngo et al 2018; Schmidt et al 2017; Yap et al 2015; Bourell et al 2017), known as 3D printing, and in particular metal additive manufacturing (AM) (Debroy et al 2018; Herzog et al 2016; Du et al 2016), has shown impressive growth, and 3D printing systems have constantly improved their performances in terms of dimensions of produced parts, precision, accuracy, and set of available materials.3D printing is constantly expanding its range of applications, and applications in fields unexpected in the past are becoming possible, ranging from cultural heritage (Taccetti et al 2019) to radiation therapy (Woo 2016).One of the most used technologies in metal AM is the powder-based fusion (PBF) (Reevesinsight 2012)
This paper shows the potential of the combined Neutron tomography (NT) and X-ray CT characterization of metal AM maraging-steel vacuum component produced using Selective Laser Melting (SLM)
For accelerator science and in general, for UHV applications, there is a strong interest in exploiting metal AM production processes for prototyping and production of special components
Summary
Additive manufacturing (AM) (Ngo et al 2018; Schmidt et al 2017; Yap et al 2015; Bourell et al 2017), known as 3D printing, and in particular metal AM (Debroy et al 2018; Herzog et al 2016; Du et al 2016), has shown impressive growth, and 3D printing systems have constantly improved their performances in terms of dimensions of produced parts, precision, accuracy, and set of available materials.3D printing is constantly expanding its range of applications, and applications in fields unexpected in the past are becoming possible, ranging from cultural heritage (Taccetti et al 2019) to radiation therapy (Woo 2016).One of the most used technologies in metal AM is the powder-based fusion (PBF) (Reevesinsight 2012). The PBF technologies used for metals are Selective Laser Melting (SLM), known as direct metal laser sintering (DSLS), and electron beam melting (EBM) (Olsén et al 2018). In EBM technology, melting of metal powder is achieved with the use of a high-energy electron beam. The most extensively studied and used metal materials in AM techniques are steels, Al alloys, Ti alloys, and Ni superalloys (Wong and Hernandez 2012; Ferreri et al 2020; Raj et al 2019). As detailed in the paragraph, SLM technology applied to maraging steel has been used to produce the part studied in this paper
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