In this research, three types of super austenitic stainless steel (SASS) with nitrogen levels of 0.2, 0.28, and 0.38 wt.% were developed. By maintaining a relatively high manganese content of approximately 1.5 wt.% and nickel content of around 18 wt.%, nitrogen was fully incorporated into the austenite, resulting in alloy samples designated as 0.2N, 0.3N and 0.4N. The hot-rolled plates of these alloys underwent a solution treatment at 1180°C for 30 min, followed by aging at 950°C for durations of 30 min, 2 h and 6 h, respectively. The influence of nitrogen content on phase precipitation behaviour was examined through various micro-structure characterisation techniques. The corrosion resistance of the samples was further evaluated using potentiodynamic polarisation experiments, Electrochemical impedance spectroscopy (EIS) and double loop-electrochemical potentiokinetic reactivation (DL-EPR) method. The results indicated that with an increase in nitrogen (N) addition, the quantity of σ phases decreased while and the formation of Cr₂N phases increased during the same aging period. Furthermore, at the same aging duration, the 0.3N SASS exhibited the highest pitting resistance and the lowest degree of sensitization (DOS) value compared to all other steels, attributed to the minimal precipitates present along the grain boundaries.

Seismoelectric coupling in an electric isotropic and elastic anisotropic medium is developed using a primary–secondary formulation. The anisotropy is of vertical transverse isotropic type and concerns only the poroelastic parameters. Based on our finite difference time domain algorithm, we solve the seismoelectric response to an explosive source. The seismic wavefields are computed as the primary field. The electric field is then obtained as a secondary field by solving the Poisson equation for the electric potential. To test our numerical algorithm, we compared our seismoelectric numerical results with analytical results obtained from Pride's equation. The comparison shows that the numerical solution gives a good approximation to the analytical solution. We then simulate the seismoelectric wavefields in different models. Simulated results show that four types of seismic waves are generated in anisotropic poroelastic medium. These are the fast and slow longitudinal waves and two separable transverse waves. All of these seismic waves generate coseismic electric fields in a homogenous anisotropic poroelastic medium. The tortuosity has an effect on the propagation of the slow longitudinal wave. The snapshot of the slow longitudinal wave has an oval shape when the tortuosity is anisotropic, whereas it has a circular shape when the tortuosity is isotropic. In terms of the Thomsen parameters, the radiation anisotropy of the fast longitudinal wave is more sensitive to the value of ε, while the radiation anisotropy of the transverse wave is more sensitive to the value of δ.