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The effects of proton irradiation on the electron work function of the 308 L austenitic stainless steel weld metal were investigated by scanning Kelvin probe force microscopy. The electron work function of ferrite increased, while austenite decreased after proton irradiation on the irradiated surface. The electron work function of the two phases decreased with irradiation depth. Softening of austenite and hardening of ferrite by irradiation with an obvious boundary between the irradiated and unirradiated regions on the polished cross-section surface were measured by nanoindentation. The corrosion morphology was consistent with the electron work function measured in the cross-section.

The degradation mechanism of trace Pb on nickel-based alloy passive film in pure water at 270 is researched by surface analysis techniques and calculations. Experimental results show that Pb reduces the oxygen content and alters the composition of the passive film, resulting in the remarkable drop in its localized electrical resistivity. Density functional theory (DFT) and thermodynamic calculation reveal that the presence of Pb has two effect on the formation of passive film. One is to retard the outward diffusion of oxygen vacancies in the oxide layer, and the other is to affect the dehydration of Cr(OH)3 and Ni(OH)2. This is a submitted manuscript of an article published by Elsevier Ltd in Corrosion Science, 5 September 2018.

The harsh environment in pressurized water reactor involving neutron irradiation and hydrogen from the water radiolysis poses significant challenges on the passivation of materials therein. Here, we probed the combined effects of hydrogen and irradiation on the oxidation of 308 L austenite stainless steel. Hydrogen lowers the electron work function of the steel. Oxide film on the irradiated and hydrogenated surface is thicker, and has a higher electrical conductivity than that on the unirradiated surface. The findings are associated with the interaction between hydrogen and irradiation-induced voids which prompts the oxidation kinetics and considerably changes the scale structure and composition.

Zn is considered as a promising degradable biomaterial. However, concerns exist for its application as the degradation mechanism of pure Zn in physiological solutions is still not clear. Results indicated that the corrosion product film showed a laminated structure with complex layers, which were ZnO/Zn(OH)2, a Ca/P phase, zinc compounds, and a Ca/P phase from the inside out, respectively. The localized corrosion initiated at grain boundaries and expanded towards the interior of grains with higher corrosion susceptibility, or advanced towards the depth. Additionally, the nature of the corrosion product film and localized corrosion synergistically determined the degradation rate.

Stress corrosion cracking (SCC) of 316 L single crystal was studied by scanning electron microscopy and electron backscatter diffraction. SCC could initiate and propagate without surface slip at the normal stress of 20 MPa. The cracks grew on the {1 0 0} planes. Many microvoids appeared at the slip bands and microsteps were present on the fracture surfaces. Consequently, the synergistic effects of microcleavage and local dissolution induced SCC advance on {1 0 0} crystal planes. Microshear was an additional SCC microscopic mechanism at high stress levels.

This study investigated the effects of dislocation patterns introduced by cold rolling deformation on the hydrogen absorption properties, hydrogen trap behaviors and hydrogen embrittlement (HE) resistance for Armco iron under electrochemical charging. The surface hydrogen coverage first increases and then decreases with increasing deformation, and reaches a maximum at 50% deformation. Dislocation cell walls appear when the deformation is greater than 50%. Furthermore, the HE resistance is improved when the deformation reaches 80%. Because the dislocation cell walls can be used as effective hydrogen traps when the dislocation density reaches a sufficiently high value.

Pitting corrosion of austenitic stainless steel weld joints served in a hydrocracking unit for 6 years was examined. The microstructure of weld metal (WM) and fusion line (FL) was austenite and ferrite. After the immersion test, many pits were observed on the FL, whereas few pits were observed on the heat-affected zone (HAZ). Pits were microscopically initiated at ferrite/austenite boundaries. Hydrogen concentrations at FL and WM were higher than those of HAZ, and hydrogen segregation occurred at ferrite/austenite boundaries, which was consistent with the pit position. Hydrogen enrichment conditions varied under different microstructures, which induced the difference in pitting susceptibility.

Passive films play an important role in corrosion and stress corrosion cracking of titanium. Correlation between passive film-induced stress and film mechanical properties on α-Ti in methanol solution with varying water content was investigated. Film-induced stress in the methanol solution was measured by the flow stress differential method, and thin film fracture properties were determined by nanoindentation. For small amounts of water (⩽0.15%), both film-induced tensile stress and film fracture load were higher. However, the film-induced tensile stress and fracture load decreased significantly in more dilute solutions. Thus, water reduces Ti SCC susceptibility in methanol solution.

The threshold stress intensity of hydrogen-induced cracking KIH, the crack propagation rate da/dt and the hydrogen diffusion coefficient D have been studied for 30CrMnSiNi2 steel. The results show a combined effect of the hydrogen concentration CH and the yield strength σys on KIH. KIH and da/dt are independent of D when σys ⩾ 1360 MPa, but KIH increases and da/dt decreases with increasing D when σys

We prepared two kinds of cracks (surface cracks and transfixion cracks) to in situ study stress corrosion cracking of seven-layered (which is denoted as 7 M or 14 M) off-stoichiometric Ni 2 MnGa magnetic shape memory alloy in deionized water and moist atmosphere under constant deflection at room temperature. The experimental results showed that the cracks could nucleate and propagate continuously or discontinuously for a distance after some incubation time, and then arrest in water or moist atmosphere under constant deflection. The delayed cracking of Ni 2 MnGa alloy is regarded as reduction of the surface energy induced by adsorption of water molecule.

In order to evaluate the protective ability of CO 2 corrosion scale to steel under flow conditions at various CO 2 partial pressures, the mechanical properties of the scale, i.e., Young′s modulus, fracture toughness, interfacial fracture toughness and adhesion strength between the scale and steel were determined by nano-indentation, Vickers’ indentation and tensile test. The influences of flow rate and CO 2 partial pressure on these mechanical properties as well as the correlations between the properties and corrosion rates were investigated. The interfacial fracture toughness between the scale and steel can evaluate the protective ability of the scale to steel effectively.