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

TL;DR

This study investigates how scratching affects the microstructure of an Al-Cu-Fe icosahedral quasicrystal using electron microscopy, revealing phase transitions, dislocation activity, and deformation features.

Contribution

It provides new insights into the microstructural changes and phase transformations induced by mechanical scratching in Al-Cu-Fe quasicrystals.

Findings

Dislocations emerge from scratch track edges.

A phase transition to b.c.c. phase occurs under shear stress.

Deformation twin and modulated quasicrystal states are observed.

Abstract

Microstructure modifications induced by sliding a WC-Co indenter in scratch tests on the surface of a single phase AlCuFe icosahedral quasicrystal (IQC) was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The scratch track was shown tocomprise many smaller tracks. Dislocations were discovered to emerge from the edges of the smaller scratch tracks. Along a small track where shear stress is concentrated, a phase transition from IQC to a body-centered cubic (b.c.c.) phase with lattice parameter a=0.29 nm was pointed out. A modulated quasicrystal state as well as a deformation twin of IQC were determined in the region beneath the scratch.