Copper and its alloys are used widely in marine environments, and anisotropic corrosion influences the corrosion kinetics of copper. Corrosion of copper in an electrolyte containing ${\mathrm{Cl}}^{-}$ is described as a dissolution–deposition process, which is a prolonged process. Therefore, it is laborious to clarify the corrosion anisotropy in different stages. In this paper, electrochemical impedance spectroscopy (EIS) following elapsed open circuit potential (OCP) test with 0 h (0H), 24 h (24H) and 10 days (10D) was adopted. To exclude interruptions such as grain boundary and neighbor effect, single crystal (SC) Cu$\left(100\right)$ and Cu$\left(111\right)$ were employed. After 10D OCP, cross-sectional slices were cut and picked up by a focused ion beam (FIB). The results showed that the deposited oxide was Cu₂O and Cu$\left(100\right)$/Cu$\left(111\right)$ experienced different corrosion behaviors. In general, Cu$\left(100\right)$ showed more excellent corrosion resistance. Combined with equivalent electrical circuit (EEC) diagrams, the corrosion mechanism of Cu$\left(100\right)$/Cu$\left(111\right)$ in different stages was proposed. In the initial stage, a smaller capacitive loop of Cu$\left(111\right)$ suggested preferential adsorption of ${\mathrm{Cl}}^{-}$ on air-formed oxide film on Cu$\left(111\right)$. Deposited oxide and exposed bare metals also played an important role in corrosion resistance. Rectangle indentations and pyramidal structures formed on Cu$\left(100\right)$/Cu$\left(111\right)$, respectively. Finally, a perfect interface on Cu$\left(100\right)$ explained the tremendous capacitive loop and higher impedance (14,274 Ω·cm²). Moreover, defects in the oxides on Cu$\left(111\right)$ provided channels for the penetration of electrolyte, leading to a lower impedance (9423 Ω·cm²) after 10D corrosion.

Accuracy of residual stress measurement using the Sin^2 ψ method has become a focus in many applications where residual stress plays a critical role in components, such as aeronautics, railway welding, bearings, gears, etc. Accuracy in residual stress measurement requires consideration of both correctness and uncertainty. In this paper, a self-designed and home-made in-situ tension/compression device is adapted to evaluate the correctness of residual stress measurement in titanium alloy. A calculation method employing multiple convolutions to evaluate the uncertainty of residual stress measurement is presented. Test results show that the X-ray elastic constant is an important parameter impacting the correctness of residual stress measurement. And that the uncertainty of residual stress measurement fluctuates with the surface status of shot peened samples.