Tuning the deformation mechanisms of boron carbide via silicon doping

Sisi Xiang, Luoning Ma, Bruce Yang, Yvonne Dieudonne, George M. Pharr, Jing Lu, Digvijay Yadav, Chawon Hwang, Jerry C. LaSalvia, Richard A. Haber, Kevin J. Hemker, Kelvin Y. Xie

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Boron carbide suffers from a loss of strength and toughness when subjected to high shear stresses due to amorphization. Here, we report that a small amount of Si doping (~1 atomic %) leads to a substantial decrease in stress-induced amorphization due to a noticeable change of the deformation mechanisms in boron carbide. In the undoped boron carbide, the Berkovich indentation–induced quasi-plasticity is dominated by amorphization and microcracking along the amorphous shear bands. This mechanism resulted in long, distinct, and single-variant shear faults. In contrast, substantial fragmentation with limited amorphization was activated in the Si-doped boron carbide, manifested by the short, diffuse, and multivariant shear faults. Microcracking via fragmentation competed with and subsequently mitigated amorphization. This work highlights the important roles that solute atoms play on the structural stability of boron carbide and opens up new avenues to tune deformation mechanisms of ceramics via doping.

Original languageEnglish (US)
Article numbereaay0352
JournalScience Advances
Volume5
Issue number10
DOIs
StatePublished - Oct 25 2019

All Science Journal Classification (ASJC) codes

  • General

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