title: In situ SEM observation of column-like and foam-like CNT array nanoindentation.
abstract: Quantitative nanoindentation of nominally 7.5 and 600 μm tall vertically aligned carbon nanotube (VACNT) arrays is observed in situ within an SEM chamber. The 7.5 μm array consists of highly aligned and weakly interacting CNTs and deflects similarly to classically defined cylindrical columns, with deformation geometry and critical buckling force well estimated using the Euler-Bernoulli theory. The 600 μm array has a highly entangled foam-like morphology and exhibits sequential buckle formation upon loading, with a buckle first forming near the array bottom at approximately 2% strain, followed by accumulating coordinated buckling at the top surface at strains exceeding 5%.
authors.affiliation: Air Force Research Laboratory, Materials and Manufacturing Directorate, AFRL/RX, Wright-Patterson Air Force Base , Ohio 45433, United States.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Maschmann
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Zhang
authors.forename: Robert
authors.initials: R
authors.lastname: Wheeler
authors.forename: Feng
authors.initials: F
authors.lastname: Du
authors.forename: Liming
authors.initials: L
authors.lastname: Dai
authors.forename: Jeffery
authors.initials: J
authors.lastname: Baur
mesh_terms: D003460:Crystallization / Q000379:methods*; D005740:Gases / Q000737:chemistry; D006244:Hardness; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D005740:Gases; D046911:Macromolecular Substances; D037742:Nanotubes, Carbon