Mechanical properties of icosahedral AlPdMn probed by indentation at variable temperatures

Hardness and elastic modulus of the icosahedral quasicrystal Al70Pd21Mn9 (i n the following simply denoted as AlPdMn) have been probed by micro- and na noindentation in the temperature range from room temperature to 820 K. Pron ounced indentation size effects (ISE) were found that,result in a hardness increase with decreasing force at room temperature and in the inverse behav iour for elevated temperatures. Furthermore, considerable indentation creep was observed for temperatures above 670 K. Atomic force microscopy (AFM) w as utilised to both quantify the impression contact area and to study the d evelopment of surface modifications and crack propagation around the indent s. The elastic modulus exhibits a linear decrease with raising temperature which is considerably smaller than observed for metals, but somewhat higher than in case of elemental semiconductors.