Title: Effect of peak stress and tensile strain-rate on spall in tantalum

Abstract

Materials subjected to dynamic environments experience a complex and wide range of stress, strain, and strain-rate conditions. To have confidence in material models, an accurate, predictive capability is required. In this study, we present a series of flyer-plate impact tests on well characterized, high purity tantalum. The shock-waves generated at impact release from the free-surfaces, reflect, and interact to produce incipient spall fracture. By varying the flyer-plate material and impact velocity, both the peak stress and the strain-rate in the samples were controlled independently. Velocimetry was used on the rear free-surface of the samples to measure the shock-response and the spall strength. While this measurement provided the same spall strength for all cases, at approximately 5.1 GPa, when the samples were sectioned during post-mortem, the quantity and distribution of internal damage was markedly different. For the high-strain rate cases, voids remained small and isolated, whereas in the lower strain-rate experiments, the spall damage was far more localized, with a well-defined continuous spall plane. With the use of hydrocode simulations, this was discovered to result from how the different release rates affect the interaction volume inside the sample. Here, these results highlight the importance of careful sample recovery, and the risksmore » of relying solely on free-surface velocity measurements.« less

Authors:

Jones, David Robert  ^[1];

• Search OSTI.GOV for author "Jones, David Robert"
• Search OSTI.GOV for ORCID "0000-0001-9466-4008"
• Search orcid.org for ORCID "0000-0001-9466-4008"

Fensin, Saryu Jindal  ^[1];

• Search OSTI.GOV for author "Fensin, Saryu Jindal"
• Search OSTI.GOV for ORCID "0000-0001-8135-5353"
• Search orcid.org for ORCID "0000-0001-8135-5353"

Martinez, Daniel Tito  ^[1];

• Search OSTI.GOV for author "Martinez, Daniel Tito"
• Search OSTI.GOV for ORCID "0000-0002-1689-7911"
• Search orcid.org for ORCID "0000-0002-1689-7911"

Trujillo, Carl Patrick ^[1]; Gray, III, George Thompson  ^[1]

• Search OSTI.GOV for author "Gray, III, George Thompson"
• Search OSTI.GOV for ORCID "0000-0002-4540-7061"
• Search orcid.org for ORCID "0000-0002-4540-7061"

---

+ Show Author Affiliations

1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Publication Date:

Wed Aug 22 00:00:00 EDT 2018

Research Org.:

Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1480043

Alternate Identifier(s):

OSTI ID: 1465907

Report Number(s):

LA-UR-18-22715
Journal ID: ISSN 0021-8979

Grant/Contract Number:  

AC52-06NA25396

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Journal of Applied Physics

Additional Journal Information:

Journal Volume: 124; Journal Issue: 8; Journal ID: ISSN 0021-8979

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE; plate-impact; strain-rate; shock; spall; tantalum