The Indentation-Induced Pop-in Phenomenon and Fracture Behaviors of GaP(100) Single-Crystal

Yi-Jui Chiu; Sheng-Rui Jian; Jyh-Wei Lee; Jenh-Yih Juang

doi:10.3390/mi10110752

The Indentation-Induced Pop-in Phenomenon and Fracture Behaviors of GaP(100) Single-Crystal

Micromachines (Basel). 2019 Nov 2;10(11):752. doi: 10.3390/mi10110752.

Authors

Yi-Jui Chiu¹, Sheng-Rui Jian², Jyh-Wei Lee^{3

4

5}, Jenh-Yih Juang⁶

Affiliations

¹ School of Mechanical and Automotive Engineering, Xiamen University of Technology, Xiamen 361024, China. chiuyijui@xmut.edu.cn.
² Department of Materials Science and Engineering, I-Shou University, Kaohsiung 840, Taiwan. srjian@gmail.com.
³ Department of Materials Engineering, Ming Chi University of Technology, New Taipei City 243, Taiwan. jefflee@mail.mcut.edu.tw.
⁴ Center for Plasma and Thin Film Technologies, Ming Chi University of Technology, New Taipei City 24301, Taiwan. jefflee@mail.mcut.edu.tw.
⁵ Department of Mechanical Engineering, Chang Gung University, Taoyuan 33302, Taiwan. jefflee@mail.mcut.edu.tw.
⁶ Department of Electrophysics, National Chiao Tung University, Hsinchu 300, Taiwan. jyjuang@g2.nctu.edu.tw.

Abstract

The deformation behaviors and fracture features of GaP(100) single-crystal are investigated by using nano- and micro-scale indentation techniques. The hardness and Young's modulus were measured by nanoindentation using a Berkovich diamond indenter with continuous contact stiffness measurements (CSM) mode and the values obtained were 12.5 ± 1.2 GPa and 152.6 ± 12.8 GPa, respectively. In addition, the characteristic "pop-in" was observed in the loading portion of load-displacement curve, which was caused by the nucleation and/or propagation of dislocations. An energetic estimation methodology on the associated nanoindentation-induced dislocation numbers resulting from the pop-in events was discussed. Furthermore, the Vickers indentation induced fracture patterns of GaP(100) single-crystal were observed and analyzed using optical microscopy. The obtained fracture toughness K_C of GaP(100) single-crystal was ~1.7 ± 0.1 MPa·m^1/2, which is substantially higher than the K_IC values of 0.8 MPa·m^1/2 and 1.0 MPa·m^1/2 previously reported for of single-crystal and polycrystalline GaP, respectively.

Keywords: GaP(100) single crystal; fracture; nanoindentation; pop-in.