Electron microscopy study of scratch-induced surface microstructures in an Al-Cu-Fe icosahedral quasicrystal

Microstructure modifications induced by sliding a WC-Co indenter in scratch tests on the surface of a single-phase Al-Cu-Fe icosahedral quasicrystal (IQC) was studied by scanning electron microscopy and transmission electron microscopy. The scratch track was shown to consist of many smaller tracks. Dislocations were discovered to emerge from the edges of the smaller scratch tracks. Along a small track where the shear stress is concentrated, a phase transition from an IQC to a bcc phase with lattice parameter a = 0.29nm was found to occur. A modulated quasicrystal state as well as a deformation twin of IQC were determined in the region beneath the scratch.