Y. Ma, V. Levitas, and J. Hashemi
Department of Mechanical Engineering, Texas Tech University
y.ma@ttu.edu
NSLS-X17C (DAC)
Superposition of plastic shear on hydrostatic pressure in a Rotational Diamond Anvil Cell (RDAC) leads to a number of new phenomena, including the reduction of the phase transformation pressure, and the formation of new phases that would not be produced without rotation. In the attempt to investigate the high pressure transformation behaviors of boron nitride under nonhydrostatic conditions with applied plastic shear, we carried out in situ x-ray diffraction measurements of boron nitride in a RDAC. We observed the transformation of hBN to wBN at 15.7 GPa with rotation. We also successfully obtained relatively homogeneous pressure in hBN and the resulting wBN, and observed the "homogeneous pressure-self multiplication effect". Further description of the RDAC and its experiments, and discussion on the transformation mechanism of hBN to wBN transformation will be presented.