Nanoquasicrystalline Al-Fe-Cr-based alloys. Part II. Mechanical properties

MARINA GALANO; FERNANDO AUDEBERT; ASUNCION GARCIA ESCORIAL; IAN STONE; BRIAN CANTOR

ACTA MATERIALIA

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2009 vol. 57 p. 5120 - 5130

1359-6454

Nanoquasicrystalline Al-based alloys show considerable promise for elevated temperature applications compared with commercial Al-based alloys. In particular, a group of Al?Fe?Cr-based alloys-containing Ti, V, Nb or Ta have outstanding thermal stability. In the present work, the elevated temperature mechanical properties of these nanoquasicrystalline alloys were studied by tensile tests at a constant strain rate. Tests were designed in order to compare the mechanical behaviour at different test temperatures. Fractographic analysis was also carried out. The apparent activation energy for plastic deformation was found to be close to that for lattice self-diffusion for pure Al in the Al?Fe?Cr ternary alloy and in the Ti-containing alloy, and for grain boundaries diffusion for pure Al in the Vcontaining alloy, whereas the activation energy of the alloy with Ta additions was three times higher. All of the alloys showed similar sensitivity of plastic deformation to the strain rate in the range of 103?5  106 s1 at 350 C. The apparent true stress exponent was napp  7, which can be associated with a deformation process controlled by dislocation mechanisms.  2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.