The oxidation behaviour of ferritic-martensitic steel P92 with different tensile stress conditions has been investigated in supercritical water at 600°C for up to 1000 h. The results indicated that the oxidation rate increased with an increase in tensile stress. The thickness of the oxide scale with atensile stress of 30 MPa is about 1.22 times greater to that at without stress, while the ratio of the thickness of oxide scale to that observed at 60 MPa is 1.73 times greater to that at 0 MPa. The thickness ratio of the outer and inner layer increased with the increasing tensile stress. Crack develops in all cases and is affected by the tensile loading. Furthermore, the thickness of the diffusion layer increased with an increase in tensile stress. The related mechanism has been discussed in this paper.

This paper reports the effects of different levels of tensile stress caused by quasi-static loading on the corrosion behavior of T91 steel in a molten salt environment. Corrosion tests were carried out in a molten salt environment with a NaCl:K₂SO₄:Na₂SO₄ ratio of 1:1:8 under different applied stresses. The corrosion behavior was investigated through measurements of the phase composition, oxide morphology, and elementary composition. The results indicated that a low tensile stress promotes the growth of chromium oxides near the substrate and enhances the corrosion resistance, but with an increase in stress, the chromium oxides that formed on the T91 steel are destroyed, accelerating the inward diffusion of sulfur into the substrate to increase corrosion. The mechanism underlying the effects of applied stress and temperature on the corrosion behavior of T91 steel is discussed.

Nickel-based alloy Inconel 617 is a candidate material for advanced ultra-supercritical units. Stress corrosion cracking (SCC) susceptibility of Inconel 617 under low-pressure superheated steam (0.1 MPa), high-pressure superheated steam (8 MPa) and supercritical water (25 MPa) at 650 °C was studied through slow strain rate tensile tests at strain rate of 5 × 10⁻⁷ s⁻¹. The results indicate that Inconel 617 is susceptible to SCC in both superheated steam and supercritical water, with susceptibility increasing with pressure. In a nitrogen atmosphere, fractures were predominantly transgranular ductile. The fracture surface featured dimples and micropores. In three corrosive environments, both intergranular and transgranular fractures were observed. The rock sugar-like morphology becomes more and more obvious as the pressure increases. A large number of cracks perpendicular to the loading axis were found on gauge surface. The SCC mechanism for Inconel 617 in superheated steam and supercritical water conditions is internal oxidation.