Determination of the controlling parameters for dislocation nucleation in SrTiO3: An investigation by nanoindentation

Wang，Xiaomei1,4; Liu，Xiaowei2; Li，Yingwei1,3,6; Fang，Xufei5

2023-10-01

10.1111/jace.19218

Journal of the American Ceramic Society   Impact Factor & Quartile

0002-7820

1551-2916

We conduct nanoindentation to investigate dislocation nucleation in SrTiO (STO) single crystals with surface orientations of (0 0 1), (0 1 1), and (1 1 1) with loading/unloading rates of 25, 250, and 2500 μN/s. Results reveal that the critical loads (P) at which “pop-in” event occurs depend strongly on surface orientations, but slightly related to loading rate. Based on P, the critical shear stress that triggers dislocation nucleation was determined by extracting the maximum resolved shear stress (τ) along the slip systems of STO using the Hertzian solution. The dislocation activation shear stress (τ) was determined by averaging τ. The determined τ is 9.0–12.0 GPa, close to the shear strength (∼G/2π) of STO, indicating that homogeneous dislocation nucleation dominates the pop-in events. The consistency of the determined τ demonstrates that the frameworks for nanoindentation pop-in analysis established for metals can be extended to ceramics, whereas the influence of the limited slip systems should be taken into consideration. Additionally, we estimated the activation volume and the activation energy via the statistical model proposed by Schuh et al. The small values of the determined activation volume (0.6–9.8 Å) and the activation energy (0.13–0.70 eV) indicate that the dislocation nucleation possibly begins from a single-atom migration and local point defects may participate in the dislocation nucleation process. That is, heterogeneous nucleation may exist initially but the homogeneous dislocation nucleation dominates the pop-in events.

activation energy activation volume dislocation nucleation nanoindentation pop-in strontium titanate

SCI

English

Corresponding

National Natural Science Foundation of China[11972262];National Natural Science Foundation of China[12272275];

Materials Science

Materials Science, Ceramics

WOS:001002213200001

WILEY

MATERIALS SCIENCE

2-s2.0-85161598291

Scopus

1.School of Civil Engineering,Wuhan University,Wuhan,Hubei,China
2.Shenzhen Institute of Advanced Electronic Materials,Shenzhen Institute of Advanced Technology,Chinese Academy of Sciences,Shenzhen,China
3.Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices,Southern University of Science and Technology,Shenzhen,Guangdong,China
4.Department of hydraulic Engineering,Hubei Water Resources Technical College,Wuhan,China
5.Department of Materials and Earth Sciences,Technical University of Darmstadt,Darmstadt,Germany
6.Technische Universität Darmstadt,Darmstadt,Germany

Wang，Xiaomei,Liu，Xiaowei,Li，Yingwei,et al. Determination of the controlling parameters for dislocation nucleation in SrTiO3: An investigation by nanoindentation[J]. Journal of the American Ceramic Society,2023,106(10):6085-6097.

Wang，Xiaomei,Liu，Xiaowei,Li，Yingwei,&Fang，Xufei.(2023).Determination of the controlling parameters for dislocation nucleation in SrTiO3: An investigation by nanoindentation.Journal of the American Ceramic Society,106(10),6085-6097.

Wang，Xiaomei,et al."Determination of the controlling parameters for dislocation nucleation in SrTiO3: An investigation by nanoindentation".Journal of the American Ceramic Society 106.10(2023):6085-6097.