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

摘要

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 degrees C) using specific deformation devices, which combined a uniaxial compression deformation or a shear deformation with a hydrostatic pressure confinement (0.35-5GPa). 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.