This symposium will focus on recent developments in the field of fracture of
thin films and small volumes, focusing on the uncovering the mechanisms
responsible for improved properties. Such novel insights are enabled by
advanced testing technologies paired with comprehensive characterization at the
nanoscale and a suited fracture-mechanical analysis. With the wide variety of
applications (semiconductors, printed electronics, energy storage, protective
coatings, etc.) and the required control of structural and functional
properties, a better understanding of the relationship between processing,
microstructures, and failure mechanisms is required to design more robust and
reliable devices and structures for use in any environment. The deformation
characteristics of thin films and small volumes have been explored for years
using different in-situ and ex-situ techniques (nanoindentation, TEM, SEM,
micro-XRD, etc). However, the need for examination of local fracture processes
calls for dedicated testing techniques that permit high temporal and local
resolution of structural and mechanical properties, ideally coupled with
measurements of electrical or thermal characteristics under applied load.
Furthermore, the enhanced understanding of the impact of interface design on
fracture in thin films and nanostructured materials is of interest. The
combination of advanced testing techniques with adapted fracture mechanics
evaluation concepts will enable a safe design of future components based on
thin films and small volumes.
The subject areas of the symposium include, but are not limited to:
• Local analysis of stress and strain around crack tips
• Fracture of nanostructured materials (thin films, printed structures,
nanocrystalline materials, …)
• Developments in nanoporous materials for energy harvesting or storage
applications
• Fracture concepts to analyze miniaturized volumes and bridge scales to
macroscopic properties
• New developments in fracture testing techniques using coupled in-situ
measurements (electrical, optical, mechanical, etc.) or in enhanced
environments (high temperatures, humidity controlled, etc.)
A joined session on fracture in harsh environments (symposium ‘Micro- and
nanomechanical testing in harsh environments’) is planned.
Interfaces constitute a key microstructural variable for tuning materials
behavior across a wide range of length scales from nano to macro in single and
multiphase systems. The advent of novel multi-phase/multi-interface
nanomaterials holds great potential for enabling unparalleled performance under
coupled extremes. Interfaces often dominate the material response in
nanostructured systems and produce unique combinations of properties that
derive from the physics of grain boundaries, phase boundaries, and/or
surfaces. A fundamental understanding of interfacial physics and coupled
phenomena impacting mechanical behavior is thus needed to harness new concepts
and methodologies in interface design for multifunctional performance.
This symposium aims to discuss interface physics that govern mechanical
behavior and coupled phenomena in interfacially-driven multifunctionality in
both single and multiphase materials. Talks are solicited that cover
fabrication, characterization, and modeling of materials with deliberately
designed interfaces with particular emphasis on new insights into fundamental
mechanisms, analysis of defects, and their implications for multifunctional
performance. Abstracts on recent developments in mechanical testing techniques
(e.g., in situ straining in TEM, micropillar testing, etc) and in high-fidelity
modeling techniques (e.g., ab initio, molecular dynamics, etc) are also
solicited. Topics of interest include, but are not necessarily limited to:
-Influence of interface structure and chemistry on deformation mechanisms
-Mechanical behavior of low dimensional materials (e.g., thin films, nanowires,
nanotubes, and nanoparticles)
-Physics of phase boundaries in multiphase systems, such as
crystalline-amorphous composites, nanolaminates, nanoparticle/matrix
composites, and nanoporous materials
-Mechanical behavior of grain boundary engineered nanomaterials (e.g. solute
stabilization, grain boundary complexion formation, duplex and gradient
nanostructures)
-Micro, meso, and macroscale modeling of deformation processes and coupled
phenomena as they relate to interface physics
-In situ testing methodologies for investigating mechanical behavior and
coupled extremes such as mechanical and irradiation of small volumes of
material
Most materials are exposed to an environment different than that found in
laboratory conditions, and it has been recognized that a material’s properties
change based on the environment to which it is exposed. Therefore,
understanding the mechanisms by which a material’s properties change in harsh
environments (e.g. high and low temperatures, high strain rate deformation, and
corrosive agents) and under non-ambient conditions is key to understanding
materials behavior in service conditions.
Micro- and nanoscale materials testing has been often utilized for a deeper
understanding of the basic phenomena of materials degradation and behavior. An
obvious next step is to expand these valuable measurements to the environments
that materials are exposed to during service conditions in order to study the
synergistic effects between harsh environments and materials property
degradation on the nanoscale. The harsh environments materials experience can
have a direct impact on the performance of nano-devices and nano-enabled energy
systems in many different applications.
Topics include:
- Nanoindentation and micromechanical testing at non-ambient conditions
- Small scale mechanical behavior under harsh environments and/or dynamic
loading conditions
- New approaches for reliable testing at elevated and low temperatures
- Accelerated testing techniques
- In-situ electrochemical loading during micromechanical testing
In 1951, Waloddi Weibull published a single-author paper describing a new
statistical distribution “of wide applicability” in the Journal of Applied
Mechanics. The very next year in the same journal, Max Williams published a
single-author paper describing an analytic stress singularity that has become
the foundation of linear elastic fracture mechanics. The Weibull distribution
provides a stress-based method for assessing the statistics of failure whereas
the Williams singularity provides a deterministic description of the stress
field at a crack tip that drives fracture. While the two approaches are quite
different, they both continue to be profoundly useful for engineering design.
The symposium will focus on application of these methods to materials science,
the limitations of these methods and nuance that has been unearthed after 65
years of use. How have these methods assisted in the development of improved
engineering materials and more reliable engineered structures? What recent
analysis methods for material failure might have a similar impact 65 years from
now? Why is recent research not as readily adopted by broad engineering
practice? What are the current generational challenges in fracture and
material failure?
Understanding the mechanics of materials in small volumes is of fundamental
importance because it simultaneously allows for the exploration of new
properties at the smallest of length scales as well as provides a basis for
understanding multiscale phenomena that originate at these lengthscales. This
symposium will focus on the mechanical properties of small-volume and
low-dimensional materials, as well as bulk materials that are comprised of or
are aggregates of these materials including bulk nanostructured materials and
nanoscale based heirarchical materials. Of particular interest are studies
that discuss sample size effects, applications of nanoscale mechanical testing
and the associated characterization, as well as modeling that addresses the
mechanical properties of these materials. Properties of interest include, but
are not limited to: elasticity, strength, plastic flow, fatigue, and fracture
with material systems ranging from hard materials, including metals and
ceramics, to soft and biological materials.
Topics will include:
- Size effects on elasticity, strength, plastic flow, fracture and fatigue in
low dimensional materials including nanopillars, nanowires, nanoparticles, thin
films, multilayered materials, graded materials, and architecture-designed
materials.
- Changes in deformation types or patterns due to changes in scale including
those due to size affected phase transformations, changes in density and types
of interfaces, as well as available deformation sources.
- Ex-situ and in-situ (SEM, TEM, XRD, neutron, etc.) mechanical
characterization methods.
- Modeling and simulation at all scales, as well as coupled scale modeling, of
mechanical behavior of nanostructured materials
- Confinement and size effects in glasses and disordered media.
- Small scale mechanics of soft matter: polymers, and biomaterials (e.g
collagen, chitin, and keratin, as well as other organic materials).
This is the tenth international symposium that focuses on all aspects of the
science and technology of ultrafine grained (UFG) and nanocrystalline
materials. This symposium covers a broad scope, ranging from fundamental
science to applications of bulk ultrafine-grained (grain size <1000 nm) and
nanostructured (feature size <100 nm) materials. It provides a forum on the
topics of fabrication and understanding of UFG and nanocrystalline materials
including conventional and emerging technologies and advancements, fundamental
issues in severe plastic deformation (SPD) processing and SPD-processed
materials, UFG and nanocrystalline microstructure evolution, mechanical and
physical properties, deformation mechanisms, superplasticity, joining and
bonding, computational and analytical modeling, structural and functional
applications, etc. Other emerging topics to be covered include gradient and
layered nanostructures, vapor-phase processing, powder processing,
rapid-solidification methods, bio-inspired nanomaterials, and radiation
tolerant nanomaterials. Also, in honor of the 10th iteration of this
symposium, we will hold a “Pioneers of Ultrafine Grained Materials” session
that will highlight the contributions of the superheroes of this field.
Awards: UFG X will be hosting a Young Scientist Session for students or
post-docs within three years of receiving their Ph.D. There will be up to two
Gold Medals and three Silver Medals for best oral presentation. Awards will
also be given for best poster (One Gold Medal and two Silver Medals). A
committee that includes the symposium organizers and invited speakers will
decide the awards. Each medalist will receive a certificate, and may receive a
cash prize, depending on resources available.