An instrument for in situ time-resolved X-ray imaging and diffraction of laser powder bed fusion additive manufacturing processes.
Rev Sci Instrum
; 89(5): 055101, 2018 May.
Article
en En
| MEDLINE
| ID: mdl-29864819
ABSTRACT
In situ X-ray-based measurements of the laser powder bed fusion (LPBF) additive manufacturing process produce unique data for model validation and improved process understanding. Synchrotron X-ray imaging and diffraction provide high resolution, bulk sensitive information with sufficient sampling rates to probe melt pool dynamics as well as phase and microstructure evolution. Here, we describe a laboratory-scale LPBF test bed designed to accommodate diffraction and imaging experiments at a synchrotron X-ray source during LPBF operation. We also present experimental results using Ti-6Al-4V, a widely used aerospace alloy, as a model system. Both imaging and diffraction experiments were carried out at the Stanford Synchrotron Radiation Lightsource. Melt pool dynamics were imaged at frame rates up to 4 kHz with a â¼1.1 µm effective pixel size and revealed the formation of keyhole pores along the melt track due to vapor recoil forces. Diffraction experiments at sampling rates of 1 kHz captured phase evolution and lattice contraction during the rapid cooling present in LPBF within a â¼50 × 100 µm area. We also discuss the utility of these measurements for model validation and process improvement.
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MEDLINE
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En
Revista:
Rev Sci Instrum
Año:
2018
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Article
País de afiliación:
Estados Unidos