Scratch-induced microstructure of Ni single crystal: A FIB-TEM study.

Revealing the scratch-induced microstructural evolution of metals is important to establish the mechanism and model of wear and/or tribology. In this work, substructure evolution of the region between scratch track and the unaffected metal of Ni single crystal was fully characterized by using advanced electron microscopy techniques such as FIB, TEM and TKD. A 30 μm × 30 μm electron transparent foil at the area of interest was fabricated by FIB technique. Four ‌characteristic substructures are identified as approaching to the scratch track direction: Area I predominantly contains dislocation cells and dislocation tangles; Area II features refined dislocation cells and cell blocks; Area III comprises ultrafine grains (UFG); Area IV consists of nanolaminates (NL). This work provides key experimental basis for relevant simulations in the field of friction and wear.