1,722,948 research outputs found
Report of International NanoSPD Steering Committee and statistics on recent NanoSPD activities
No full textThe Université de Lorraine in Metz, France, is the selected site for the 6th International Conference on Nanomaterials by Severe Plastic Deformation (NanoSPD6) following a series of five earlier conferences. This introductory paper reports on several major developments in NanoSPD activities as well as on very recent NanoSPD citation data which confirm the continued growth and expansion of this important research area. Close attention is given to the topics of workshops, conferences and seminars organized during these last three years as well as on books and reviews published prior to the NanoSPD6 conference. A special concern of the committee is in introducing and discussing the appropriate terminology to be applied in this new field of materials science and engineerin
Chapter 1 - High-pressure torsion and equal-channel angular pressing
No full textIn this chapter, the main peculiarities of ultrafine-grained (UFG) structure formation in commercially pure Ti is examined when processing by high-pressure torsion (HPT) or equal-channel angular pressing (ECAP). High-pressure torsion is used to produce Ti with extremely small grain sizes (generally < 100 nm). The ECAP technique was developed in the 1990s by R.Z. Valiev and coauthors and successfully used to produce UFG structures in bulk billets of pure Ti. Recently, this technique was further developed and a number of modifications of the technique have been proposed, including continuous ECAP or ECAP-Conform which enables the production of long-length rods (up to 1 m)
Developments in the use of ECAP processing for grain refinement
No full textEqual-channel angular pressing (ECAP) is one of the most efficient techniques of severe plastic deformation for the production of bulk ultrafine-grained metals. During the last decade the intensive developments of ECAP have been associated with numerous modifications of the die-set design as well as establishing new processing routes and regimes. This paper describes the various types of ECAP that have been developed recently and applied for grain refinement. Special attention is focused both on new trends in ECAP processing associated with the development of continuous processing and on its efficiency
X-ray Peak Profile Analysis on the Microstructure of Al-5.9%Mg-0.3%Sc-0.18%Zr Alloy Deformed by High Pressure Torsion Straining
No full textThe microstructure of plastically deformed Al-5.9%Mg-0.3%Sc-0.18%Zr alloy has been
investigated. The severe plastic deformation has been performed by high pressure torsion
straining (HPT) up to 15 revolutions at room temperature. The microstructure as a function of
the number of revolutions is studied by X-ray diffraction peak profile analysis. It is concluded
that the HPT technique results in nanostructure even after 0.5 turn with very high dislocation
density. The crystallite size decreases and the dislocation density increases with the number of
revolutions, however, after five turns they go into saturation. The edge and the dipole
character of the dislocation structure becomes stronger with the increase of the number of
revolutions. The value of the crystallite size determined by X-ray peak profile analysis is a bit
smaller than the grain size obtained by transmission electron microscopy (TEM)
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The art and science of tailoring materials by nanostructuring for advanced properties using SPD techniques
No full textIn recent years a breakthrough has developed in the studies of nanostructured metals and alloys as advanced structural and functional materials associated both with the development of new routes for the fabrication of bulk nanostructured materials using severe plastic deformation (SPD) and with investigations of the fundamental mechanisms that lead to the new properties of these materials. This review paper discusses new concepts and principles in using SPD processing to fabricate bulk nanostructured metals with advanced properties. Special emphasis is placed on the relationship between microstructural features and properties, as well as the innovation potential of SPD-produced nanomaterials.<br/
Achieving exceptional grain refinement through severe plastic deformation: new approaches for improving the processing technology
No full textThe processes of equal-channel angular pressing (ECAP) and high-pressure torsion (HPT) are now established for the fabrication of ultrafine-grained metals having superior properties by comparison with their coarse-grained counterparts. This article examines the recent developments designed to improve the processing technology of ECAP and HPT and to establish these techniques as viable procedures for use in industrial applications. Based on these developments, it is reasonable to anticipate these processing procedures will experience increasing use in the fabrication of commercial product
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