A new prediction model for pitting corrosion damage considering both pit initiation and pit growth was presented. The pit initiation was modeled based on a combination of the Sridhar model and Macdonald model, and the critical potential was redefined at the same time. The pit initiation time can be divided into the time in which the open circuit potential (OCP) exceeds the repassivation potential (E_rp), and the pit induction time, when OCP > E_rp. The pit growth was modeled using the Markov process and extreme value statistics were used to describe the maximum pit depth distribution. If the time–consuming pit initiation process is neglected, it results in unacceptable errors in the pit growth kinetics parameters obtained. Thus, an acceleration method, the pre-initiated pits method, was developed to eliminate this negative effect. The proposed model was validated using experimental data on the pitting corrosion of 304 stainless steel (SS) and reproduces the experimental observations with high fidelity.

In the past decades, the durability of thermal barrier coatings (TBCs) has been extensively studied. The majority of researches emphasized the problem of oxidation, corrosion, and erosion induced by foreign object damage (FOD). TBCs with low thermal conductivity are usually coated on the hot-section components of the aircraft engine. The main composition of the TBCs is top-coat, which is usually regarded as a wear-resistant and heat-insulating layer, and it will significantly improve the working temperature of the hot-section components of the aircraft engine. The application of TBCs are serviced under a complex and rigid environment. The external parts of the TBCs are subjected to high-temperature and high-pressure loading, and the inner parts of the TBCs have a large thermal stress due to the different physical properties between the adjacent layers of the TBCs. To improve the heat efficiency of the hot-section components of aircraft engines, the working temperature of the TBCs should be improved further, which will result in the failure mechanism becoming more and more complicated for TBCs; thus, the current study is focusing on reviewing the failure mechanism of the TBCs when they are serviced under the actual high temperature conditions. Finite element simulation is an important method to study the failure mechanism of the TBCs, especially under some extremely rigid environments, which the experimental method cannot realize. In this paper, the research progress of the failure mechanism of TBCs at high temperature via finite element modeling is systematically reviewed.

The influence of rare earth element (RE) Y on the microstructure and corrosion behavior of extruded AZ91 Mg alloy was surveyed via morphology characterization and corrosion performance measurements. The results indicate the corrosion resistance of the transversal section of AZ91 Mg alloy containing Y was improved compared with AZ91 Mg alloy without Y. The corrosion resistance of the longitudinal section of AZ91 Mg alloy with Y was lower than that of AZ91 Mg alloy without Y. The change of corrosion resistance can be attributed to the dispersion and volume fraction of the second phase, the effect of cathodic reduction rate, and the refined second phase.

The development characteristics of land subsidence of Xi'an by an advanced InSAR technique are investigated based on Envisat, Radarsat-2 and Sentinel-1 satellites, and it can be found that there still have been five typical land subsidence bowls with maximum subsidence rates beyond 40 mm/year in Xi'an. In 2012, the land subsidence took on slightly slowing down with a ground rebound area of up to 6.3 km². But in 2003–2010, 2016 and 2017, there was more serious land subsidence and especially in 2017 the maximum velocity reached up to −137 mm/year. Yuhuazhai-Nanyaotou subsidence bowl as the greatest subsidence bowl, its area that rate was below 50 mm/year in 2017 was up to 10.64 km². Moreover, these land subsidence bowls mainly concentrate upon tectonic depression area due to huge thickness clay soil and are spatially and temporally coincident with confined aquifer depression cones, suggesting that over-exploitation groundwater plays a decisive role for land subsidence. Ground fissure belts are generally controlled by normal faults in Xi'an, but asymmetry settlement of land surface can also give rise to the abnormal activities of ground fissure belts, which have caused serious threat or damage to building structures. In addition, it could also be found that surface uplift area in 2012 involves in both the tectonic depression area and loess ridge in terms of their same thickness sand layer.

Reliability and durability are two important performance indicators for thermal barrier coatings (TBCs). The reliability of TBCs usually includes high adhesive strength, low thermal conductivity and high thermal shock resistance. The high reliability of TBCs ensures basic usage requirements. Durability demands TBCs have a long service lifetime before their eventual failure. The lifetimes of TBCs under actual service conditions are strongly dependent on crack initiation and propagation. Controlling and delaying the dynamic process of crack initiation and propagation is a direct approach to prolonging the service lifetime of TBCs. Self-healing TBCs usually have the specific function of inhibiting crack propagation, and thus promote the self-healing process of TBCs. The research progress of self-healing TBCs was reviewed. Firstly, the concept of self-healing or self-healing materials is clarified. Secondly, the research progress about some self-healing ceramic materials as well as self-healing TBCs is reviewed. Based on the review, the micro-structure design, propagation patterns of the crack and self-healing mechanism are discussed systematically. Additionally, the future development trend of the self-healing TBCs is also overviewed in this paper.