Al–Pd–Mn icosahedral quasicrystal: deformation mechanisms in the brittle domain

Abstract

The extreme brittleness of Al–Pd–Mn quasi-crystalline alloys over a wide range of temperatures drastically restricts investigation of their plastic deformation mechanisms over a small high-temperature regime. Recently, plastic deformation of Al–Pd–Mn quasicrystal has been achieved in the brittle domain (20 ≤ T ≤ 690°C) using specific deformation devices, which combined a uniaxial compression deformation or a shear deformation with a hydrostatic pressure confinement (0.35–5 GPa). Results of these experimental techniques, which provide various deformation conditions giving rise to a range of Al–Pd–Mn plastic features in the brittle domain, are discussed. On this basis, we propose that low and intermediate temperature plastic properties of Al–Pd–Mn are controlled by non-planar dislocation core extensions specific to the non-periodic structure.

Acknowledgments

The authors are indebted to Dr M. Feuerbacher for providing Al–Pd–Mn single quasicrystals. Professor P. Guyot is gratefully acknowledged for helpful discussions. ‘Région Poitou–Charentes’ is also acknowledged for financial support.