PLASTIC-DEFORMATION IN ICOSAHEDRAL AL-PD-MN ALLOYS

The deformation characteristics of icosahedral Al70Pd21.5Mn8.5 have be en investigated by high temperature creep experiments, and the resulta nt microstructures have been examined by transmission electron microsc opy (TEM). From 730 to 780 degrees C, microstructural analysis reveale d that the deformation is controlled by dislocation glide, with an act ivation energy of 210 +/- 30 kJ/mole and a stress exponent of 1.2 +/- 0.2. From 780 to 810 degrees C, microstructures were characteristic of deformation controlled by dislocation glide and climb. The activation energy and stress exponent were determined to be 1700 +/- 80 kJ/mole and 2.9 +/- 0.3, respectively. Hardness measurements also reflected an increase in dislocation density, as the hardness of the deformed samp les was approximately 10% higher than the as-cast sample.