Title: Understanding the evolution of liquid and solid microjets from grooved Sn and Cu samples using radiography

Abstract

Experiments were performed on grooved Sn and Cu samples to study the temporal evolution of microjets. Jets were generated by the impact of gun-launched flyer plates against the back of grooved targets made from either Cu or Sn (groove depth of ~250 μm). The Hugoniot states in the various Sn targets encompassed conditions where solid phases are maintained throughout (7 and 16 GPa) and also conditions where melting occurs upon the release of compression (25 and 34 GPa); the transition occurs near a Hugoniot pressure of 23 GPa. Cu targets at 27 and 56 GPa provide comparisons in which the jets move at similar speeds but remain solid. In all cases, the spatial distribution of mass within the microjets was measured using high-speed synchrotron radiography. The result is a time history of the jet thickness profile from which quantities like total jet mass and jet velocity can be derived. In both the solid and liquid states, we generally observe that an increase in the shock strength leads to an increase in jet mass. However, this trend breaks down for Hugoniot states near the transition from continuously solid to melted-on-release. This is evidenced by the observation that there was no differencemore » in the rate of mass flow in Sn jets at 16 and 25 GPa, while similar pressure jumps on either side of this range caused substantial changes in the jet mass. This contrasts with the behavior of smaller polishing defects that were present on the same samples (~1 μm deep). From these, no ejecta mass was detected below the melt boundary, but obvious microjets were generated once melting occurred. This indicates that crossing the bulk melt-on-release threshold can alternately promote or inhibit the flow of mass into microjets based on the amplitude of the initial perturbation.« less

Authors:

Bober, David B.  ^[1];

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• Search DOE PAGES for ORCID "0000-0003-1608-781X"

Mackay, Kyle K.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-8978-2242"

Akin, Minta C.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-5742-8663"

Najjar, Fady M.  ^[1]

• Search DOE PAGES for author "Najjar, Fady M."
• Search DOE PAGES for ORCID "0000-0001-8078-5562"

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+ Show Author Affiliations

1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Publication Date:

Thu Jul 22 00:00:00 EDT 2021

Research Org.:

Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Washington State Univ., Pullman, WA (United States). Inst. for Shock Physics

Sponsoring Org.:

USDOE Office of Science (SC); USDOE National Nuclear Security Administration (NNSA), Office of Defense Programs (DP)

OSTI Identifier:

1812058

Alternate Identifier(s):

OSTI ID: 1809106; OSTI ID: 1827505; OSTI ID: 1873902; OSTI ID: 1873904

Report Number(s):

LLNL-JRNL-821093
Journal ID: ISSN 0021-8979; APS_262776; TRN: US2213215

Grant/Contract Number:  

AC02-06CH11357; AC52-07NA27344; NA0003957; NA0003579

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Applied Physics

Additional Journal Information:

Journal Volume: 130; Journal Issue: 4; Journal ID: ISSN 0021-8979

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

ENGLISH

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; hydrodynamics; flow instabilities; shock compression; tin; copper; radiography; shock wave experiments; phase transitions; Materials science