Nanoindentation Stress Relaxation to Quantify Dislocation Velocity–Stress Exponent

Chang, Tzu-Yi; Vandenbroeder, Gavin; Frazer, David M.; Yushu, Dewen; Pitts, Stephanie; Chen, Tianyi

doi:10.3390/cryst14080680

Open AccessArticle

Nanoindentation Stress Relaxation to Quantify Dislocation Velocity–Stress Exponent

by

Tzu-Yi Chang

¹

,

Gavin Vandenbroeder

¹,

David M. Frazer

^2,†,

Dewen Yushu

²,

Stephanie Pitts

²

and

Tianyi Chen

^1,*

¹

School of Nuclear Science and Engineering, Oregon State University, Corvallis, OR 97330, USA

²

Idaho National Laboratory, 1955 Fremont Ave, Idaho Falls, ID 83415, USA

^*

Author to whom correspondence should be addressed.

^†

Current address: General Atomics, San Diego, CA 92121, USA.

Crystals 2024, 14(8), 680; https://doi.org/10.3390/cryst14080680

Submission received: 3 July 2024 / Revised: 18 July 2024 / Accepted: 22 July 2024 / Published: 26 July 2024

(This article belongs to the Special Issue Characterization and Modelling of the Deformation and Failure of Engineering Metallic Materials)

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Abstract

This work reports a new methodology using indentation stress relaxation to characterize the dislocation velocity–stress exponent. Through the indentation stress relaxation process, the dislocation structure builds up at the rate governed by dislocation velocity, which is a function of the externally applied stress. The relationship between the dislocation velocity and stress can thus be derived from the indentation stress relaxation data of the stress as a function of time. In this study, instrumented nanoindentation stress relaxation experiments were performed on pure aluminum samples, following three different initial displacement rates of 100, 400, and 800 nm/s. Based on the scaling properties of dislocation kinetics, the data were interpreted to derive a dislocation velocity–stress exponent of 2.5 ± 0.5 for room-temperature aluminum. Crystal plasticity finite-element simulations were performed to illustrate the sensitivity of the proposed nanoindentation stress relaxation methodology to the dislocation velocity–stress exponent value.

Keywords: scaling; nanomechanics; creep; activation volume

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MDPI and ACS Style

Chang, T.-Y.; Vandenbroeder, G.; Frazer, D.M.; Yushu, D.; Pitts, S.; Chen, T. Nanoindentation Stress Relaxation to Quantify Dislocation Velocity–Stress Exponent. Crystals 2024, 14, 680. https://doi.org/10.3390/cryst14080680

AMA Style

Chang T-Y, Vandenbroeder G, Frazer DM, Yushu D, Pitts S, Chen T. Nanoindentation Stress Relaxation to Quantify Dislocation Velocity–Stress Exponent. Crystals. 2024; 14(8):680. https://doi.org/10.3390/cryst14080680

Chicago/Turabian Style

Chang, Tzu-Yi, Gavin Vandenbroeder, David M. Frazer, Dewen Yushu, Stephanie Pitts, and Tianyi Chen. 2024. "Nanoindentation Stress Relaxation to Quantify Dislocation Velocity–Stress Exponent" Crystals 14, no. 8: 680. https://doi.org/10.3390/cryst14080680

APA Style

Chang, T.-Y., Vandenbroeder, G., Frazer, D. M., Yushu, D., Pitts, S., & Chen, T. (2024). Nanoindentation Stress Relaxation to Quantify Dislocation Velocity–Stress Exponent. Crystals, 14(8), 680. https://doi.org/10.3390/cryst14080680

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

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Nanoindentation Stress Relaxation to Quantify Dislocation Velocity–Stress Exponent

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