Nanoscale Depth Profiling of Residual Stresses Due to Fine Surface Finishing

Abstract

Mechanical polishing is commonly used for both surface finishing and metallographic sample preparation for a broad range of materials. However, polishing causes local deformation and induces residual stress, which has an important effect on many surface phenomena. Until recently, it has not been possible to quantify the nanoscale depth variation of polishing‐induced plastic deformation (eigenstrain) and the associated residual stress. In this study, the magnitude and depth of polishing‐induced residual stress are evaluated directly by focused ion beam milling and digital image correlation using the micro‐ring‐core geometry method. Depth‐resolved residual stress profiles are obtained with sub‐micrometer resolution at the surface of a titanium alloy sample that is subjected to various polishing steps. It is found that electrochemical polishing and polishing with colloidal silica do not induce any significant residual stress. However, polishing with diamond slurry leads to the formation of compressive residual stresses of up to 300 MPa, which extend deeper into the material when larger diamond particles are used. This study paves the way for further research on polishing and its effect on surface properties.

Mechanical properties of thermally grown submicron oxide layers on a nickel-based superalloy

“…The formation of Al2O3 from the γ' phase (Ni3Al in the simplified case) results in a transformation strain of around 466 % [21], which means that the formation of these finger-like intrusions is indeed expected to cause compressive residual stress. The surface preparation prior to oxidation could also have an influence, since it has been shown recently that polishing with diamond slurry induces compressive residual stresses up to a few micrometers in depth [52]. Additionally, the current results show for the first time that the ring-core FIB-DIC technique is capable of providing depth-resolved residual stress profiles in native oxide layers with submicron thickness.…”

Quantifying residual stress in Helium-implanted surfaces and its implication for blistering

“…The Vanadium single crystal sample (control) shows insignificant tensile residual stress within the experimental error. A recent study has shown that mechanical polishing does not induce any significant residual stress and hence the sample can be considered as stress free [21].…”

Modelling and Characterisation of Residual Stress of SiC-Ti3C2Tx MXene Composites Sintered via Spark Plasma Sintering Method

“…The maps of stress distribution on the polished surface and fracture surfaces obtained on this basis confirm these assumptions. However, it should be emphasized that polishing the surface can significantly affect the state of internal stress [ 57 ], and the diamond suspensions of various sizes used in the polishing process may change the nature of stresses at a depth of up to several hundred nanometres [ 58 , 59 ]. This can significantly distort the information regarding the stresses that remain on the polished surface.…”