Chalmers Conferences, The 6th Swedish Production Symposium

IDENTIFICATION OF THEORETICAL SHEAR STRENGTH AND ONSET OF YIELDING IN CUBIC BORON NITRIDES VIA NANOINDENTATION
S. Dub, I. Petrusha, V. Bushlya, G. Tolmacheva, A. Andreev

Last modified: 2014-11-25

Abstract


The onset of plasticity in cubic boron nitride (cBN) was studied by nanoindentation with continuous stiffness measurement (CSM) option. CSM option allows us to observe elastic-plastic transition in the contact and to measure the yield strength of cBN at nanoscale. In single crystals with low dislocations density sharp elastic-plastic transition (pop-in) was observed as a result of homogeneous dislocations nucleation at shear stress close to theoretical shear strength (G/2π). For near nanocrystalline cBN sample the smooth elastic-plastic transition was observed as a result of propagation of already existing dislocations in the region of contact.


Keywords


cBN, nanoindentation, elasto-plastic transition, theoretical shear strength

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