Bulk nanostructured materials are defined as solids with nanoscale (typically 1-100 nm) substructures. In recent years, bulk nanostructured materials have been the subjects of intensive research due to their superior physical and mechanical properties. These include a combination of high strength and ductility at room temperature, high strain rate and low temperature superplasticity, ductility in usually brittle ceramics and intermetallics, and high saturation magnetization and coercive force in magnetic materials. These superior mechanical and physical properties make nanostructured materials attractive for numerous advanced applications in medical, aerospace, sporting goods, and transportation industries.

Various methods for producing nanostructured materials have been developed, which, based on their approaches, can be classified into two categories. The first is the "bottom up" approach, which builds materials atom by atom or atom cluster by atom cluster. Methods in this category include inert gas condensation and other nanopowder production methods. Nanopowder production technologies are well developed, and various metallic, as well as ceramic, powders are commercially available. Powder consolidation, however, has been largely unsuccessful. The heat and pressure applied during the powder consolidation also promotes the grain growth, which makes materials lose their nanocharacteristics. So far, only penny-sized bulk nanomaterials have been produced, which are too small for any structural applications. Other problems with powder consolidation methods include high cost, contamination, and porosity.

The second approach for producing nanostructured materials is the "top down" approach, which refines coarse-grained metals through severe plastic deformation (SPD). The most developed SPD techniques are equal channel angular pressing (ECAP) and high-pressure torsion (HPT). Recently, new SPD techniques have been developed, such as accumulative roll bonding, repetitive corrugation and straightening, and twist extrusion. SPD techniques have the capability of producing bulk nanostructured materials large enough for structural applications. In addition, the nanostructured materials produced by SPD are 100 percent dense and contamination free. Therefore, the SPD techniques offer significant advantages over others in synthesizing bulk nanostructured materials.

Due to the great commercialization potential, the research and development activities on SPD and SPD-processed materials have increased exponentially in recent years, as evidenced by the increase in papers published on the topic. Recent publications indicate that high pressures during SPD significantly affect the microstructural evolution, and consequently the mechanical properties of bulk nanostructured materials. For example, the HPT technique, which exerts the highest hydrostatic pressure, can refine grains most effectively and produces the finest nanostructures among all SPD techniques. When high back-pressure is used during ECAP, the processed materials can sustain larger processing strain without fracture. High pressure is believed to reduce porosity, cracks, and other macroscopic defects that are detrimental to mechanical properties.

Recently it was reported that nanostructured materials processed under high pressure by HPT and ECAP have an extraordinary combination of both high strength and high ductility - two desirable, but rarely co-existing properties. These findings indicate that high pressure is a critical factor that can be employed to process nanostructured materials with superior mechanical, and possibly also physical, properties. The reports on high pressure effects are mostly fragmental, however, and there has been no systematic effort to study the high-pressure effect on the processing and properties of nanostructured materials. Neither has this issue been adequately addressed in recent conferences on nanostructured materials. Recently, processing nanostructured materials by SPD under high-pressures has caught the attention of the scientific community and will become one of the major research and development thrusts in the next few years. The objective of this workshop is to review our current knowledge, identify issues for future research, and discuss future directions on the processing and properties of nanostructured materials via high-pressure SPD. This workshop will accelerate the development of nanostructured materials for real world commercial applications.

The scope of the workshop includes, but is not limited to:
1. Reviewing our current knowledge of the high pressure effect on the nanostructures and properties of SPD-processed materials.
2. Identifying issues with SPD processing under high pressure for future research and development.
3. Discussing the development of high-pressure SPD technologies for commercial production of nanostructured materials.
4. Identifying applications and future markets of SPD-processed nanostructured materials.

This workshop brings together experts in several relevant fields - including Materials Science, Plastic Deformation Mechanics, Computer Modeling, High Pressure Physics and Pressure Treatment Technologies - to discuss the high-pressure effect on the nanostructures and properties of SPD-processed materials. The complexity of the issues demands such a diverse expertise. This unique approach brings together experts with different academic backgrounds and experience, thus developing new ideas for solving critical scientific issues. Most participants will be invited according to their expertise and academic reputation.

The workshop's agenda is as follows:

SPD experts will report on the current status and recent advancements of SPD-processing of nanostructured materials and their properties. This will update other experts, in the fields of plastic deformation mechanics, high pressure physics and metal forming technology who are not currently involved in SPD, on the current state of SPD and its issues.

Experts in the fields of plastic deformation mechanics, high pressure physics and metal forming technology will report on their work applicable to the SPD processing of nanostructured materials.



ACCOMPANYING PERSON

Participants may bring an accompanying person, who is invited to participate in the welcome party, the conference dinner, all tours, and other social activities.


LANGUAGE

English will be the official language of the meeting.


NATO ARW brochure You can download here.

You are visitor:

Last updated: 09.16.2004