The impact of nanoindentation at room temperature upon the real structure of decagonal AlCoNi quasicrystals
Physica Status Solidi a-Applications and Materials Science 202(12): 2267-2276
Plastic deformation of the quasicrystalline decagonal phase Al72Co9Ni19, which appears macroscopically brittle at room temperature, has been performed by nanoindentation. Employing high resolution transmission electron microscopy it could be shown that near indents regions of a nanocrystalline phase appeared, which was identified. as trigonal Al-3(Ni,Co)(2). So, for permanent deformation at room temperature no dislocation movement was needed. Instead, it seems reasonable to assume that the decagonal phase tends to decompose into a crystalline phase under stress. Values of nanohardness and elastic modulus determined during this work were found within the range of data reported so far by other authors. (c) 2005 WILEY-VCH Veriag GmbH & Co. KGaA, Weinheim.