Hillock growth phenomena during post-indentation annealing of quasicrystalline AlPdMn

Single-quasicrystalline icosahedral AlPdMn was subject to Vickers microinde ntations at room temperature, annealed up to 750 degrees C in vacuum, and t hen inspected using optical microscopy, atomic force microscopy (AFM), wave length dispersive microanalysis (WDX) and Auger spectroscopy (AES). At temp eratures above 600 degrees C the whole sample surface became increasingly r ough, exhibiting holes and small elevations, whereas the vicinity of the im pressions remained free of surface alterations. The growth of large hillock s out of the impressions was observed at temperatures above 700 degrees C i n the presence of oxygen. No growth of high elevations was noted for an oxy gen partial pressure below 3 x 10(-6) Pa. AES and WDX revealed an enrichmen t of manganese and the depletion of aluminium in the hillocks. The results are discussed in the frame of indentation induced defects and their impact on diffusion and surface migration.