Publication Date

5-1-2018

Department

Ames Laboratory

Campus Units

Ames Laboratory

OSTI ID+

1438740

Report Number

IS-J 9686; LLNL-JRNL-739736

DOI

10.1063/1.5017236

Journal Title

Review of Scientific Instruments

Volume Number

89

Issue Number

5

First Page

055101

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 ∼1.1 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 ∼50 × 100 μm area. We also discuss the utility of these measurements for model validation and process improvement.

DOE Contract Number(s)

AC52-07NA27344; CPA 32035; CPA 32037; CPA 32038

Language

en

Department of Energy Subject Categories

36 MATERIALS SCIENCE; 42 ENGINEERING; 47 OTHER INSTRUMENTATION; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS

Publisher

Iowa State University Digital Repository, Ames IA (United States)

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