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Elevated temperature mechanical behaviour of nanoquasicrystalline Al$_{93}$Fe$_{3}$Cr$_{2}$Ti$_{2}$ alloy and composites

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Galano, M 
Audebert, F 
Smith, G 

Abstract

Rapidly solidified nano-quasicrystalline Al93Fe3Cr2Ti2 at% alloy has previously shown outstanding tensile and compressive strength and microstructural stability up to elevated temperatures. Despite this, no study had previously assessed the effect of plastic deformation at elevated temperature to simulate thermal-mechanical forging processes for the production of engineering components. The present work analysed bars consisting of a nano-quasicrystalline Al93Fe3Cr2Ti2 at% alloy matrix, with the addition of 10 and 20 vol% pure Al ductilising fibres, produced through gas atomisation and warm extrusion. The microstructure was made primarily of nanometre-sized icosahedral particles in an α-Al matrix. Compression tests were performed across a range of temperatures and strain rates. The measured yield strength at 350 °C was over 3x that of “high strength” 7075 T6 Al alloy, showing outstanding thermal stability and mechanical performance. However, the microstructure was shown by XRD to undergo a phase transformation which resulted in the decomposition of the icosahedral phase around ~500 °C into more stable intermetallic phases. Serrated flow associated with dynamic strain ageing was observed and a semi-quantitative analysis matching elemental diffusion speeds with dislocation speed at specific strain rates was performed, which tentatively identified Ti as the solute species responsible within the selected range of temperatures and strain rates.

Description

Keywords

quasicrystals, aluminium, fibre composite, dynamic strain ageing, mechanical properties

Journal Title

Materials Science & Engineering: A

Conference Name

Journal ISSN

0921-5093
1873-4936

Volume Title

705

Publisher

Elsevier
Sponsorship
M. Galano thanks RAEng and EPSRC for their financial support through EP/G05794X/1. F. Audebert thanks UBACyT20020130100663 and PIDDEF31/14 for financial support.