Modeling and Experiment of the Critical Depth of Cut at the Ductile-Brittle Transition for a 4H-SiC Single Crystal

Peng Chai; Shujuan Li; Yan Li

doi:10.3390/mi10060382

Modeling and Experiment of the Critical Depth of Cut at the Ductile-Brittle Transition for a 4H-SiC Single Crystal

Micromachines (Basel). 2019 Jun 7;10(6):382. doi: 10.3390/mi10060382.

Authors

Peng Chai¹, Shujuan Li², Yan Li³

Affiliations

¹ School of Mechanical and Precision Instrument Engineering, Xi'an University of Technology, No. 5 South Jinhua Road, Xi'an 710048, Shaanxi, China. chaipeng@stu.xaut.edu.cn.
² School of Mechanical and Precision Instrument Engineering, Xi'an University of Technology, No. 5 South Jinhua Road, Xi'an 710048, Shaanxi, China. shujuanli@xaut.edu.cn.
³ School of Mechanical and Precision Instrument Engineering, Xi'an University of Technology, No. 5 South Jinhua Road, Xi'an 710048, Shaanxi, China. jyxy-ly@xaut.edu.cn.

Abstract

In this paper, a theoretical model of the critical depth of cut of nanoscratching on a 4H-SiC single crystal with a Berkovich indenter is proposed, and a series of scratch tests in a nanomechanical test system was performed. Through nanoindentation experimentation on fused quartz, the Berkovich indenter nose radius was indirectly confirmed using least squares. The range of critical depths of cut at the ductile-brittle transition was obtained by SEM observation, and the size of cracks was amplified with increasing scratching depth. The theoretical result of the critical depth of cut at the ductile-brittle transition for a 4H-SiC single crystal is 91.7 nm, which is close to the first obvious pop-in point of the relation curve between tangential force and lateral displacement. Repeated experimental results show good consistency and good agreement with other references.

Keywords: 4H-SiC; Berkovich indenter; cleavage strength; critical depth of cut; nanoscratching.

Abstract

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