FP6 priority

1.1.3   Nanotechnologies and Nanosciences, Knowledge-based Multifunctional Materials and New Production Processes and Devices

1.3.1

Title of the proposal

Development of bulk nanostructured aluminium based materials prepared by Equal-Channel Angular Pressing of nanopowders or amorphous ribbons

Institute

Slovak Academy of Sciences, Institute of Materials and Machine Mechanics
Racianska 75, 831 02 Bratislava 3, Slovak Republic

Contact

Research subject for a potential FP6 project

Equal-Channel Angular Pressing (ECAP) is a recently developed method for deformation processing of polycrystalline alloys that can produce an ultrafine-grained (UFG) nanostructured material through severe plastic deformation. This procedure introduces large shear stresses into the rod-shaped bulk material without any change in the cross-sectional area of sample and allows repeated processing for several cycles to attain very high plastic strains. However the final grain size in a case of Al/alloys lies typically within the submicrometer instead of nanometer range and the structure is very instable leading to substantial grain growth at elevated temperature. The proposed approach uses powders or ribbons as starting material for ECAP instead of bulk rod. Such starting material will be made of aluminum alloys by rapid quenching methods in order to obtain amorphous or very fine-grained structure already before pressing. The high shear stresses at relatively low pressing forces at ECAP will be used for compacting of nanostructured particulate precursor without need to increase the pressing temperature significantly. Using this approach the grain size of starting material can be stabilized via additions of metal (phase) atoms segregating in grain boundary. The dynamic recrystalisation will be reduced as well using high strain rates for pressing.
The purpose is to assess the mechanical properties of ECAP materials, both their benefits and drawbacks, in order to disclose the perspective fields of their applications and optimise their properties.

Recent international cooperation of the research team

Schwabische Huttenwerke G.m.b.H., Aalen - Wasseralfingen, Germany
Mepura, Metallpulvergesellschaft m.b.H., Ranshofen, Austria
Boehler Uddeholm AG, Austria
Institute of Chemical Technologies and Analytics, TU Wien

Proposer´s relevant publications related to the research subject

1. J. JERZ, “Foamed Aluminium and Aluminium Alloys Prepared by Powder Metallurgy“, PhD thesis, TU Vienna, 1995
2. SIMANCIK, F., Jangg, G.: Influence of processing parameters on fibre damage and mechanical properties of extruded composite with aluminium matrix and short carbon fibres. In: Theoretical and Applied Fracture Mechanics, 1994, vol. 20, p. 11-20.
3. IZDINSKY, K., et.al: Microstructure of the as plasma sprysed NiCrAlY coating. Kovove mater. 36, 1998, p.367.