Lower-bound dislocation density mapping in microcoined tantalum using high-resolution electron backscatter diffraction

Journal Article · Sun May 05 00:00:00 EDT 2019 · Materials Characterization

DOI:https://doi.org/10.1016/j.matchar.2019.04.033· OSTI ID:1561216

Randall, Greg C. ^[1]; Hansen, Kameron R. ^[2]; Jackson, Brian ^[2]; Fullwood, David T. ^[2]

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1. General Atomics, San Diego, CA (United States)
2. Brigham Young Univ., Provo, UT (United States)

High-resolution electron backscatter diffraction (HR-EBSD) is used to map the geometrically necessary dislocation (GND) density in the cross-sections of annealed, rolled, and microcoined tantalum foils that are typical targets used in modern laser-induced compression materials science studies. The microcoined samples are characteristic of microforming, where the deformation length scale is on the order of the grain size (~50 μm). Specifically, inhomogeneities in dislocation density maps across 0.1–1mm regions of interest are compared with expectations from slip line field approximations. Here, the average HR-EBSD GND dislocation density measurements in various annealed and cold worked tantalum samples are compared with corresponding dislocation density approximations from microhardness measurements. GND densities in the range 10¹³ - 10¹⁵ m^-2 are typical.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• Grant/Contract Number: FC02-04ER54698; SC0012587
• OSTI ID: 1561216
• Alternate ID(s): OSTI ID: 1702920
• Journal Information: Materials Characterization, Vol. 153, Issue C; ISSN 1044-5803
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Dislocation density
EBSD
Metals
Microstructure formation
Microforming
Coining