Transformation-induced plasticity and cascading structural changes in hexagonal boron nitride under high pressure and shear

Valery I. Levitas, Yanzhang Ma, Javad Hashemi

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In situ x-ray diffraction study and modeling of the degree of disorder, s, and phase transformation (PT) in hexagonal hBN were performed. It was proven that changes in s are strain-induced and that s can be used to quantify plastic strain. During the strain-induced hBN→wurtzitic wBN PT, the transformation-induced plasticity (TRIP) was exposed and quantified. TRIP exceeds conventional plasticity by a factor of 20. Cascading structural changes were revealed. Strain-induced disorder explains why PT under hydrostatic and nonhydrostatic conditions started at the same pressure ∼10 GPa. For the same disorder, plastic shear reduces PT pressure by a factor of 3-4.

Original languageEnglish
Article number071912
Pages (from-to)1-3
Number of pages3
JournalApplied Physics Letters
Issue number7
StatePublished - Feb 14 2005


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