Advances in the measurement of hardness at high strain rates by nanoindentation

Hackett, B.; Phani, P. Sudharshan; Walker, Christopher C.; Oliver, W. C.; Pharr, George M.

doi:10.1557/s43578-023-00921-1

Cited by 20 publications

(17 citation statements)

References 30 publications

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“…Arrays of Berkovich indentations were produced using a specially designed high-strain-rate nanoindentation system based on a modified InForce 1000 nanoindenter actuator head (KLA Instruments, Oak Ridge, TN) ( 8 ). As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…1 A , the capacitive gauge normally used to measure the displacement was replaced by a laser interferometer with a 10-pm displacement resolution and capable of acquiring data at a rate of 1.25 MHz. The enhanced data acquisition rate increases the time resolution needed to measure indentation depths and loads during high-strain-rate experiments ( 8 ). With this modification, the system is capable of operating over a wide range of indentation strain rates (

, where h and

are the depth and depth rate) ranging from quasistatic tests (

~ 10 −4 -10 −2 s −1 ) up to impact tests (

> 10 4 s −1 ) ( 8 , 9 , 35 ).…”

Section: Resultsmentioning

confidence: 99%

“…The enhanced data acquisition rate increases the time resolution needed to measure indentation depths and loads during high-strain-rate experiments ( 8 ). With this modification, the system is capable of operating over a wide range of indentation strain rates (

, where h and

are the depth and depth rate) ranging from quasistatic tests (

~ 10 −4 -10 −2 s −1 ) up to impact tests (

> 10 4 s −1 ) ( 8 , 9 , 35 ). Quasistatic tests were conducted at constant indentation strain rate

through feedback control of the loading rate ( 36 ).…”

Section: Resultsmentioning

confidence: 99%

“…The load–depth curves and hardness values of the corresponding indents were calculated following procedures developed by Hackett et al ( 8 ). The testing system can probe mechanical properties over 9 orders of magnitude of indentation strain rate in a single testing platform, which helps to strengthen the understanding of deformation mechanisms over a wide range of strain rate.…”

Section: Resultsmentioning

confidence: 99%

“…While machine-learning aided materials informatics promises to dramatically accelerate materials design and discovery ( 2 ), validating materials characterization and performance through standard high-strain-rate testing techniques, i.e., plate impact ( 3 ), split Hopkinson bar ( 4 – 6 ), and gas gun impact ( 7 ), still remains a bottleneck in the high-strain-rate materials design cycle due to the low throughput nature and high cost of these testing techniques. In this regard, high-strain-rate nanoindentation has recently emerged as a potentially useful high-throughput testing technique ( 8 ), but it remains unclear whether small-scale measurements adequately capture material deformation behavior at macroscopic scales ( 9 – 12 ).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Evolution of dislocation substructures in metals via high-strain-rate nanoindentation

Zhang,

Hackett,

Dong

et al. 2023

Proc. Natl. Acad. Sci. U.S.A.

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Deformation at high strain rates often results in high stresses on many engineering materials, potentially leading to catastrophic failure without proper design. High-strain-rate mechanical testing is thus needed to improve the design of future structural materials for a wide range of applications. Although several high-strain-rate mechanical testing techniques have been developed to provide a fundamental understanding of material responses and microstructural evolution under high-strain-rate deformation conditions, these tests are often very time consuming and costly. In this work, we utilize a high-strain-rate nanoindentation testing technique and system in combination with transmission electron microscopy to reveal the deformation mechanisms and dislocation substructures that evolve in pure metals from low (10 –2 s –1 ) to very high indentation strain rates (10 4 s –1 ), using face-centered cubic aluminum and body-centered cubic molybdenum as model materials. The results help to establish the conditions under which micro- and macro-scale tests can be compared with validity and also provide a promising pathway that could lead to accelerated high-strain-rate testing at substantially reduced costs.

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Section: Resultsmentioning

confidence: 99%

, where h and

are the depth and depth rate) ranging from quasistatic tests (

~ 10 −4 -10 −2 s −1 ) up to impact tests (

> 10 4 s −1 ) ( 8 , 9 , 35 ).…”

Section: Resultsmentioning

confidence: 99%

, where h and

are the depth and depth rate) ranging from quasistatic tests (

~ 10 −4 -10 −2 s −1 ) up to impact tests (