https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Inoue-ActaMater00-Stabilization%20of%20metallic%20supercooled%20liquid%20and%20bulk%20amorphous%20alloys.pdf

Stabilization of metallic supercooled liquid and bulk amorphous alloys

A balanced mechanics-materials approach and coverage of the latest developments in biomaterials and electronic materials, the new edition of this popular text is the most thorough and modern book available for upper-level undergraduate courses on the mechanical behavior of materials To ensure that the student gains a thorough understanding the authors present the fundamental mechanisms that operate at micro- and nano-meter level across a wide-range of materials, in a way that is mathematically simple and requires no extensive knowledge of materials This integrated approach provides a conceptual presentation that shows how the microstructure of a material controls its mechanical behavior, and this is reinforced through extensive use of micrographs and illustrations New worked examples and exercises help the student test their understanding Further resources for this title, including lecture slides of select illustrations and solutions for exercises, are available online at wwwcambridgeorg/97800521866758

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Mechanical Behavior of Materials

https://www.tcd.ie/Physics/people/Graham.Cross/SF%20Poster%202011/Schuh-ActaMater07-Mechanical%20behaviour%20of%20amorphous%20alloys.pdf

Mechanical behavior of amorphous alloys

Carbon nanotube–polymer composites: Chemistry, processing, mechanical and electrical properties

Hexagonal ferrites: A review of the synthesis, properties and applications of hexaferrite ceramics

This text provides an understanding of the relationship between structure, processing, and properties of materials. By selecting the appropriate topics from this wealth of material, instructors can emphasize materials, provide a general overview, concentrate on mechanical behavior, or focus on physical properties. Since the book has more material than is needed for a one-semester course, students will also have a useful reference for subsequent courses in manufacturing, materials, design, or materials selection.

The science and engineering of materials

We have studied the mechanical behavior of Zr 40 Ti 14 Ni 10 Cu 12 Be 24 through uniaxial compression and nanoindentation experiments. Quantitative measurements of the serrated plastic flow observed during uniaxial compression are reported. These data are used to predict temperature increases in single shear bands due to local adiabatic heating caused by the work done on the sample as shear propagates progressively across the sample. Since the predicted temperature increases are insufficient to reach the glass transition temperature, it is unlikely that localized heating is the primary cause of flow localization. Instead, localization of shear is more likely caused by changes in viscosity associated with increased free volume in the shear bands. The orientation of the shear bands in compression tests and an indentation size effect for the onset of plastic flow in nanoindentation both point to increased free volume as the cause of localization.

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Deformation Mechanisms of the Zr40Ti14Ni10Cu12Be24 Bulk Metallic Glass

We have studied the serrated plastic flow observed in Zr40Ti14Ni10Cu12Be24 and Pd40Ni40P20 bulk metallic glass alloys tested in uniaxial compression. Quantitative measurements with sufficient temporal resolution to record the fine-scale structure of the data are reported. These data are used to predict temperature increases in single shear bands due to local adiabatic heating caused by the work done on the sample during plastic deformation. Since the predicted temperature increases are on the order of only a few degrees Kelvin, it seems unlikely that localized heating is the primary cause of flow localization. Instead, changes in viscosity associated with increased free volume in the shear band seem more consistent with experiment. Substantial shear band heating is, however, predicted for final failure, as corroborated by evidence of melting on the fracture surface.

Localized heating during serrated plastic flow in bulk metallic glasses

We have investigated the possibility of void nucleation from the coalescence of excess free volume generated in shear bands during deformation of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 bulk metallic glass. Excess free volume in a shear band results in excess free energy relative to a relaxed glass with less free volume. To calculate the free energy of the material in a shear band with excess free volume, we model it as having the same structure as a glass solidified at an elevated glass transition temperature, which we call the fictive temperature. This excess free energy can be correlated with a free volume chemical potential that provides a driving force for void nucleation. The results of this modeling indicate that any free volume generated in the shear band during deformation is unstable, with the consequence that voids are predicted to form spontaneously from the coalescence of free volume. These voids are then expected to coarsen. Under tension, void growth and linkage would be facilitated by a tensile stress state, perhaps leading to premature fracture, whereas a compressive stress state would hinder void growth. This may explain the common observation that failure under uniaxial tension occurs as the result of the propagation of a single shear band, whereas multiple shear bands can form under uniaxial compression without causing failure.

Free volume coalescence and void formation in shear bands in metallic glass

For the first time in metallic glasses, we extract both the exponents and scaling functions that describe the nature, statistics, and dynamics of slip events during slow deformation, according to a simple mean field model We model the slips as avalanches of rearrangements of atoms in coupled shear transformation zones (STZs) Using high temporal resolution measurements, we find the predicted, different statistics and dynamics for small and large slips thereby excluding self-organized criticality The agreement between model and data across numerous independent measures provides evidence for slip avalanches of STZs as the elementary mechanism of inhomogeneous deformation in metallic glasses

Wendelin J. Wright

Papers

The science and engineering of materials

Deformation Mechanisms of the Zr40Ti14Ni10Cu12Be24 Bulk Metallic Glass

Localized heating during serrated plastic flow in bulk metallic glasses

Free volume coalescence and void formation in shear bands in metallic glass

Bulk metallic glasses deform via slip avalanches.