Thin boron nitride nanotubes with exceptionally high strength and toughness

Abstract

Bending manipulation and direct force measurements of ultrathin boron nitride nanotubes (BNNTs) were performed inside a transmission electron microscope. Our results demonstrate an obvious transition in mechanics of BNNTs when the external diameters of nanotubes are in the range of 10 nm or less. During in situ transmission electron microscopy bending tests, characteristic "hollow" ripple-like structures formed in the bent ultrathin BNNTs with diameters of sub-10 nm. This peculiar buckling/bending mode makes the ultrathin BNNTs hold very high post-buckling loads which significantly exceed their initial buckling forces. Exceptional compressive/bending strength as high as ∼1210 MPa was observed. Moreover, the analysis of reversible bending force curves of such ultrathin nanotubes indicates that they may store/adsorb strain energy at a density of ~400 × 10(6) J m(-3). Such nanotubes are thus very promising for strengthening and toughening of structural ceramics and may find potential applications as effective energy-absorbing materials like armor.

Large variations in the onset of rippling in concentric nanotubes

“…3,4 During bending the tubes can however deform in buckling or rippling patterns, much like macroscopic tubes do, and the bending stiffness will drop significantly. Such deformations have been observed for nanotubes made of C, 5,6 BN, 7,8 and WS 2 , 9 while similar deformations are also expected to occur in MoS 2 .…”

The Mechanical Properties of Nanowires

“…Owing to its simplicity and efficiency in operation, the resonant vibration testing was widely used to determine the elastic modulus of NWs including Si, Ge, Co, W, SiC, GaN, Ag 2 Ga, BN, ZnO, WO 3 , In 2 O 3 , Sb 2 O 3 , Al 2 O 3 , amorphous SiO 2 , metallic glasses . In particular, the use of SLDV not only significantly increases the detection resolution of a NW specimen's vibrational spectra, but also eliminates the issues relating to clamping and dimensional non‐uniformity .…”

A comparison between the mechanical and thermal properties of single-walled carbon nanotubes and boron nitride nanotubes

“…Besides that BNNTs possess better thermal and oxidation stability than CNTs [7][8][9][10]. CNTs and BNNTs are promising components as reinforcements in composites for enhenced mechanical and thermal properties in micro/nano-electro-mechanical devices [11][12][13][14][15][16][17][18].…”