A Multi-technique tomography-based approach for non-invasive characterization of additive manufacturing components in view of vacuum/UHV applications; Preliminary results

Grazzi, F.*; Cialdai, C.*; Manetti, M.*; Massi, M.*; Morigi, M. P.*; Bettuzzi, M.*; Brancaccio, R.*; Albertin, F.*; 篠原 武尚; 甲斐 哲也; et al.

Rendiconti Lincei. Scienze Fisiche e Naturali, 32(3), p.463 - 477, 2021/09

https://doi.org/10.1007/s12210-021-00994-2

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.

Investigation of microstructure in additive manufactured Inconel 625 by spatially resolved neutron transmission spectroscopy

Tremsin, A. S.*; Gao, Y.*; Dial, L. C.*; Grazzi, F.*; 篠原 武尚

Science and Technology of Advanced Materials, 17(1), p.324 - 336, 2016/07

AA2016-0560.pdf:3.26MB

https://doi.org/10.1080/14686996.2016.1190261

Non-destructive testing techniques based on neutron imaging and diffraction can provide information on the internal structure of relatively thick metal samples (up to several cm), which are opaque to other conventional non-destructive methods. Spatially resolved neutron transmission spectroscopy is an extension of traditional neutron radiography, where multiple images are acquired simultaneously, each corresponding to a narrow range of energy. The analysis of transmission spectra enables studies of bulk microstructures at the spatial resolution comparable to the detector pixel. In this study we demonstrate the possibility of imaging (with about 100 m resolution) distribution of some microstructure properties, such as residual strain, texture, voids and impurities in Inconel 625 samples manufactured with an additive manufacturing method called direct metal laser melting (DMLM).

Archaeometallurgy study of Japanese sword using neutron diffraction

Harjo, S.; 及川 健一; 川崎 卓郎; Grazzi, F.*; 篠原 武尚; 田中 眞奈子*; Pham, A.*; 森戸 茂一*; 鬼柳 善明*; 伊藤 正和*

no journal, , 

We used neutron diffraction mapping measurements to elucidate the Japanese sword's microstructure and discuss the manufacturing procedures. Mapping measurements using pulsed neutron diffraction with time-of-flight method were performed on a full-shape and test pieces of Japanese sword. The obtained diffraction patterns are analyzed by the Rietveld refinement and a line profile analysis. The constituent phases in the area closer to the back of the blade (ridge) are found to be ferrite and cementite, composing pearlite, while the area close to the edge is composed by martensite and austenite. The distributions of constituent phases are well explained with the distributions of dislocation density and crystallite size.