title: Breaking the icosahedra in boron carbide.
abstract: Findings of laser-assisted atom probe tomography experiments on boron carbide elucidate an approach for characterizing the atomic structure and interatomic bonding of molecules associated with extraordinary structural stability. The discovery of crystallographic planes in these boron carbide datasets substantiates that crystallinity is maintained to the point of field evaporation, and characterization of individual ionization events gives unexpected evidence of the destruction of individual icosahedra. Statistical analyses of the ions created during the field evaporation process have been used to deduce relative atomic bond strengths and show that the icosahedra in boron carbide are not as stable as anticipated. Combined with quantum mechanics simulations, this result provides insight into the structural instability and amorphization of boron carbide. The temporal, spatial, and compositional information provided by atom probe tomography makes it a unique platform for elucidating the relative stability and interactions of primary building blocks in hierarchically crystalline materials.
authors: Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218.
authors: Kelvin Y
authors: KY
authors: Xie
authors: Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125.
authors: Qi
authors: Q
authors: An
authors: Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006, Australia.
authors: Takanori
authors: T
authors: Sato
authors: Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006, Australia; School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia.
authors: Andrew J
authors: AJ
authors: Breen
authors: Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006, Australia; Australian Institute for Nanoscale Science and Technology, The University of Sydney, Sydney, NSW 2006, Australia.
authors: Simon P
authors: SP
authors: Ringer
authors: Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125.
authors: William A
authors: WA
authors: Goddard
authors: Australian Centre for Microscopy and Microanalysis, The University of Sydney, Sydney, NSW 2006, Australia; School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW 2006, Australia.
authors: Julie M
authors: JM
authors: Cairney
authors: Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218; Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD 21218 hemker@jhu.edu.
authors: Kevin J
authors: KJ
authors: Hemker
keywords: ab initio molecular dynamics; bond dissociation; laser-assisted atom probe tomography; multiple hits