nanomaterials. mechanics and mechanisms, 2009, p.142

[...]... nanocrystalline and ultrafine grain sizes on constitutive behavior and shear bands in iron July 2003, with permission from Elsevier 204 6.14 Shear band patterns evolve with strain in compressed ultra-finegrain Fe (Wei et al., 2002) Note the propagation of existing shear bands, the nucleation of new shear bands, and the thickening of existing shear bands The development... first band Note that no failure (in terms of void growth) is evident at the intersection of the shear bands Reprinted from Acta Materialia, Vol 51, Issue 12, page 15, D Jia, K.T Ramesh, E Ma, Effects of nanocrystalline and ultrafine grain sizes on constitutive behavior and shear bands in iron July 2003, with permission from Elsevier 206 6.16 TEM micrographs (a) within and (b) outside a shear band in... nanoscale and microscale can dominate the behavior and performance of devices and structures in the centimeter to 100 m range Most of the behaviors of interest to this book arise from length scales of 0.1–100 nm, and this will be our definition of “the nanoscale.” One way to distinguish between nanotechnology and nanoscience is by distinguishing between what we can control and what we can understand Most... nanoscale phenomena are either controlled or modulated by the mechanics at the nanoscale, and so mechanics plays a critical role in nanoscience Nanomechanics controls phenomena as immediately obvious as the interaction of interfaces between nanosize crystals and as subtle as the folding of proteins (controlling and organizing the living cell) The mechanics of nanomaterials is therefore the focus of this... scales in mechanics and materials and in nature The topics of interest to this book cover a large part of this scale domain, but are controlled by features and phenomena at the nm scale Note the sophistication of natural materials and systems at very small length scales 1 Nanomaterials 3 the largest animals are blue whales, coming in at about 100 m, comparable in size to some aircraft Phenomena and features... shear bands is also observed Reprinted from Applied Physics Letters, Vol 81, Issue 7, pages 1240–1242, Q Wei, D Jia, K.T Ramesh, E Ma, Evolution and microstructure of shear bands in nanostructured fe 2002, with permission from American Institute of Physics 205 6.15 (a) Shearing deformation across one band and (b) the stable intersection of multiple shear bands... orientation fraction (φ ) around the band center Note the rapid early growth, the spatial localization, and the saturation of φ Also note the spreading of the band, i.e., the increasing band thickness - this is also observed in experiments 248 ˙ 7.18 Evolution of plastic shear strain rate (γ p ) around the band center The greatest activity in this variable is at the band boundaries, where the grains... fine grained X-Ray Diffraction xv List of Figures 1.1 1.2 1.3 1.4 1.5 1.6 Length scales in mechanics and materials and in nature The topics of interest to this book cover a large part of this scale domain, but are controlled by features and phenomena at the nm scale Note the sophistication of natural materials and systems at very small length scales ... positions in the two configurations with material and spatial vectors 284 8.11 Range of experimental measurements of the elastic modulus of carbon nanotubes, as summarized by Zhang et al (2004) Note the theoretical predictions discussed here were 705 GPa (Zhang et al., 2002) and 1385 GPa (Volokh and Ramesh, 2006) Reprinted from Journal of the Mechanics and Physics of Solids, P Zhang, H Jiang,... modulus of carbon nanotubes, as summarized by Zhang et al (2004), including a wide variety of first principles and MD simulations Note the theoretical predictions discussed here were 705 GPa (Zhang et al., 2002) and 1385 GPa (Volokh and Ramesh, 2006) Reprinted from Journal of the Mechanics and Physics of Solids, P Zhang, H Jiang, Y Huang, P.H Geubelle, K.C Hwang, An atomistic-based continuum theory . similar apparatus) (a) SEM image showing a single-crystal copper tension sample and the corresponding tungsten sample gripper before the test at a low magnification. (b) Sample and gripper aligned prior. Single crystal copper specimen and tension gripper for in situ tensile testing in the SEM, from the work of the group of Dehm, Kiener et al. (this group has also performed compression experiments using. paper Springer is part of Springer Science+Business Media (www.springer.com) To Arjun, Rohan and Priti, for your love and patience. Preface This book grew out of my desire to understand the mechanics