Sat, 26 Jul 2008 17:10:34 BST CiteULike: dchen Spaepen http://www.citeulike.org/user/dchen/author/Spaepen CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dchen/article/2746726 <i>(1974)</i> PERCOLATION THEORY AND CONDUCTIVITY OF RANDOM CLOSE PACKED MIXTURES OF HARD SPHERES Spaepen (1974) 2008-05-02T18:11:13-00:00 1974 spaepen http://www.citeulike.org/user/dchen/article/2746714 <i>(1974)</i> MECHANISM FOR FLOW AND FRACTURE OF METALLIC GLASSES F Spaepen (1974) 2008-05-02T18:07:53-00:00 1974 alloy glass spaepen http://www.citeulike.org/user/dchen/article/2719217 <i>Journal of Applied Physics, Vol. 97, No. 3. (2005)</i><br /><br />View This Record in Scopus Creation and annihilation of free volume during homogeneous flow of a metallic glass Marc Heggen Frans Spaepen Michael Feuerbacher Journal of Applied Physics, Vol. 97, No. 3. (2005) 2008-04-25T18:33:49-00:00 2005 Journal of Applied Physics 97 3 AIP freevolume shear http://www.citeulike.org/user/dchen/article/2710365 <i>Science, Vol. 305, No. 5692. (24 September 2004), pp. 1944-1948.</i><br /><br />The dominant mechanism for creating large irreversible strain in atomic crystals is the motion of dislocations, a class of line defects in the crystalline lattice. Here we show that the motion of dislocations can also be observed in strained colloidal crystals, allowing detailed investigation of their topology and propagation. We describe a laser diffraction microscopy setup used to study the growth and structure of misfit dislocations in colloidal crystalline films. Complementary microscopic information at the single-particle level is obtained with a laser scanning confocal microscope. The combination of these two techniques enables us to study dislocations over a range of length scales, allowing us to determine important parameters of misfit dislocations such as critical film thickness, dislocation density, Burgers vector, and lattice resistance to dislocation motion. We identify the observed dislocations as Shockley partials that bound stacking faults of vanishing energy. Remarkably, we find that even on the scale of a few lattice vectors, the dislocation behavior is well described by the continuum approach commonly used to describe dislocations in atomic crystals. 10.1126/science.1102186 Visualization of Dislocation Dynamics in Colloidal Crystals Peter Schall Itai Cohen David Weitz Frans Spaepen doi:10.1126/science.1102186 Science, Vol. 305, No. 5692. (24 September 2004), pp. 1944-1948. 2008-04-23T22:01:50-00:00 2004 Science 305 5692 1944 1948 cohen schall science shear weitz http://www.citeulike.org/user/dchen/article/553502 <i>Nature, Vol. 440, No. 7082., pp. 319-323.</i> Visualizing dislocation nucleation by indenting colloidal crystals Peter Schall Itai Cohen David Weitz Frans Spaepen doi:10.1038/nature04557 Nature, Vol. 440, No. 7082., pp. 319-323. 2006-03-15T23:36:35-00:00 Nature 0028-0836 440 7082 319 323 Nature Publishing Group defect schall shear weitz http://www.citeulike.org/user/dchen/article/2674721 <i>Acta Metallurgica, Vol. 30, No. 2. (February 1982), pp. 447-455.</i><br /><br />Inhomogeneous flow in metallic glasses is studied in this paper within the context of continuum mechanics. Motivated by similar work for elastic-plastic solids, the possibility of strain localization into a shear band is investigated for a metallic glass which is modelled as a nonlinear viscoelastic solid. The essential features of the localization problem are brought out through an analysis of the constitutive law which reveals a catastrophic softening via free volume creation. Analytic expressions for the stress at catastrophic softening agree very closely with the stress at strain localization calculated from the numerical solution of the full set of shear band equations. Strain localization in amorphous metals PS Steif F Spaepen JW Hutchinson doi:10.1016/0001-6160(82)90225-5 Acta Metallurgica, Vol. 30, No. 2. (February 1982), pp. 447-455. 2008-04-15T18:11:44-00:00 1982 Acta Metallurgica 30 2 447 455 shear stz http://www.citeulike.org/user/dchen/article/2670976 <i>Acta Metallurgica, Vol. 25, No. 4. (April 1977), pp. 407-415.</i><br /><br />An empirical deformation map for metallic glasses is introduced and the two modes of deformation, homogeneous and inhomogeneous flow are reviewed. The microscopic mechanism for steady state inhomogeneous flow is based on a dynamic equilibrium between stress-driven creation and diffusional annihilation of structural disorder. The formalism is developed using the free volume as the order parameter. The boundary line between the homogeneous and inhomogeneous flow regions on the deformation map is calculated. The stress-strain relation in inhomogeneous flow approaches ideally plastic behavior. A microscopic mechanism for steady state inhomogeneous flow in metallic glasses Frans Spaepen doi:10.1016/0001-6160(77)90232-2 Acta Metallurgica, Vol. 25, No. 4. (April 1977), pp. 407-415. 2008-04-15T01:17:38-00:00 1977 Acta Metallurgica 25 4 407 415 classic shear stz http://www.citeulike.org/user/dchen/article/2453811 <i>Science, Vol. 318, No. 5858. (21 December 2007), pp. 1895-1899.</i><br /><br />Structural rearrangements are an essential property of atomic and molecular glasses; they are critical in controlling resistance to flow and are central to the evolution of many properties of glasses, such as their heat capacity and dielectric constant. Despite their importance, these rearrangements cannot directly be visualized in atomic glasses. We used a colloidal glass to obtain direct three-dimensional images of thermally induced structural rearrangements in the presence of an applied shear. We identified localized irreversible shear transformation zones and determined their formation energy and topology. A transformation favored successive ones in its vicinity. Using continuum models, we elucidated the interplay between applied strain and thermal fluctuations that governs the formation of these zones in both colloidal and molecular glasses. 10.1126/science.1149308 Structural Rearrangements That Govern Flow in Colloidal Glasses Peter Schall David Weitz Frans Spaepen doi:10.1126/science.1149308 Science, Vol. 318, No. 5858. (21 December 2007), pp. 1895-1899. 2008-03-01T21:29:01-00:00 2007 Science 318 5858 1895 1899 colloids flow schall shear stz weitz