Elevated temperature mechanical behaviour of nanoquasicrystalline Al93Fe3Cr2Ti2 alloy and composites

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:705

Article

Pedrazzini, S.^1,2  Galano, M.²  Audebert, F.^2,3,4  Smith, G. D. W.² 

[1] Univ Cambridge, Dept Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS, England

[2] Univ Oxford, Dept Mat, Parks Rd, Oxford OX1 3PH, England

[3] Univ Buenos Aires, Fac Ingn, INTECIN CONCET UBA, Adv Mat Grp, Paseo Colon 850, RA-1063 Buenos Aires, DF, Argentina

[4] Oxford Brookes Univ, Dept Mech Engn & Math Sci, Wheatley Campus, Oxford OX33 1HX, England

关键词: Quasicrystals;    Aluminium;    Fibre composite;    Dynamic strain ageing;    Mechanical properties;   

DOI  :  10.1016/j.msea.2017.08.075

来源: Elsevier

【 摘 要 】

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 alpha-Al matrix. Compression tests were performed across a range of temperatures and strain rates. The measured yield strength at 350 degrees 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 degrees 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.

【 授权许可】

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