Bulk Nanostructured Materials with Superior Properties for Innovation Applications
In recent years the development of bulk nanostructured metallic materials has become one of the most topical directions in modern materials science. Nanostructuring of metals and alloys paves the way to obtaining unusual properties that are very attractive for innovative applications [1, 2]. In this research topic, the use of severe plastic deformation (SPD) techniques attracts special attention since it offers new opportunities for developing new technologies of fabrication of various large semi-products from nanostructured materials in the form of sheets, rods, thin foils, wire, for various specific applications [2, 3]. Recent years also witness the transition of SPD methods such as high pressure torsion (HPT), equal channel angular pressing (ECAP) and others from laboratory scale to commercial techniques based on continuous processes, for example ECAP-Conform. These new trends are considered with details in the present lecture.
Especially significant progress has been made recently in the development of physical principles of enhancement of nanomaterials properties. It is well-known that nanostructured metals and alloys very often demonstrate high strength at the expense of ductility and may even be brittle, which hinders their wide application as structural materials.
We demonstrate in this talk that application of grain boundary (GB) engineering principles, i.e. generation of mostly high-angle grain boundaries with nonequilibrium, strain-distorted structure  or formation of GB segregations and precipitations makes it possible to achieve unique combination of multifunctional properties in nanomaterials [5, 6]. As a result we can produce the materials with high fatigue strength, endurance, increased fracture toughness. The examples of successful realization of these principles applied to enhance the properties in a number of commercial alloys based on Al, Ti and steels are given in the report. Also first pilot articles for innovative applications in medicine and engineering as well as ways of their commercialization are considered and discussed.
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- R. Z. Valiev, Y. Estrin, Z. Horita, T. G. Langdong, M. J. Zehetbauer, Y.T. Zhu, Producing bulk ultrafine-grained materials by severe plastic deformation: ten years later, JOM (2016) DOI: 10.1007/s11837-016-1820-6