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Laser surface texture (LST) technology can be used to increase the adherence of thermal barrier coating (TBC). The primary research method is to conduct a large number of laser experiments to determine the optimal texture parameters. To minimize costs and enhance efficiency, in the current work, five types of circular pit textures were summarized; the plane strain model was established using the transient thermomechanical coupling finite element method; the residual stress field after spraying was used as the prestress field; the influence of different textures on the distribution of the residual stress field after a thermal cycling was analyzed; and the propagation law of cracks in the coating was predicted. The current work focuses on: (1) The two-dimensional cross-sectional morphology of texture; (2) the principal stress s 22 perpendicular to the interface (resulting in mode I interface crack) and the shear stress s 12 parallel to the interface (resulting in mode II interface crack); (3) texture variables—diameter, depth, and spacing. The results revealed that after thermal cycling, the texture in the ceramic top coat (TC) bore tensile stress of around 350 MPa. Both sides of the pit in the metallic bond coat (BC) bore tensile stress, while the bottom bore compressive stress. Among them, the positive tensile stress of the texture with a sinusoidal section was the greatest, whereas the shear stress was the least. The maximum stress in texture increased as the diameter and depth increased, while the minimum principal stress was obtained by adjusting the spacing among the adjacent textures. The stress level in the coating was reduced by selecting the appropriate texture morphology, and the crack propagation was more complex, that is, it took a longer time before reaching failure, which is expected to improve the life. [ABSTRACT FROM AUTHOR]

• The gradient porosity anode is adopted for the design of a planar SOFC. • The gradient porosity anode can reduce the maximum first principal stress of the components by 20.0 % at room temperature and 44.9 % under the operating condition. • The influence of gradient porosity anodes on the residual stress is analyzed for the first time. • The residual stress and thermal stress of the anode-supported SOFC were analyzed, and the effect of porosity change on stress state was analyzed. Residual stresses and thermal stresses in solid oxide fuel cells (SOFCs) are the main factors to induce the reliability degradation including delamination, cracking and damage. Anode porosity is potential controller to the stresses due to the effects on the mechanical compatibility of SOFC components and electrochemical reaction rate. Herein, we establish a three-dimensional SOFC multi-physics field coupling model to explore the electrochemical and mechanical performance of SOFCs employing gradient porosity anode versus uniform porosity anode. The influence of porosity on the carrier conduction, gas flow, gas diffusion and transfer, and heat transfer in porous composite electrodes are considered. The results indicate that the gradient porosity anode significantly enhances the mechanical compatibility of SOFC components while maintaining high electrochemical performance. At room temperature, the dangerous area of residual stress occurs at the anode, and the gradient porosity anode can reduce the maximum first principal stress of the anode by 20.0 %. Under the operating condition, the dangerous area of thermal stress occurs in the electrolyte, and the gradient porosity anode can reduce the maximum first principal stress of the electrolyte by 44.9 %. Additionally, it significantly alleviates stress concentration in the SOFC. This study provides a way to optimize the reliability of SOFCs by controlling the anode porosity. [ABSTRACT FROM AUTHOR]

Waterjet peening is a promising new surface treatment technology, which is increasingly used to improve a metal's surface integrity and mechanical properties. In this study, the surface integrity and solid particle erosion (SPE) resistance of Ti-6Al-4V alloy treated with submerged deflecting abrasive waterjet peening (SDA-WJP) at different standoff distances (D = 3, 6, and 9 mm) were investigated. First, the surface integrity of specimens before and after SDA-WJP treatment was compared, including microstructure, surface roughness, micromorphology, microhardness, and compressive residual stress (CRS). The test results showed that the SDA-WJP-treated specimens formed refined grain deformation layers of 8–24 μm and minimum roughness of Ra = 0.28 μm and Sa = 0.55 μm. The thicknesses of the refined grain hardening layer and CRS field were 140–180 and 120–200 μm, respectively. Finally, the SPE behavior and mechanism of the samples before and after SDA-WJP treatment were studied in the SPE test. The highest increase in SPE resistance was 51 % under different SDA-WJP processes. The microscopic morphology of the eroded surface was observed by scanning electron microscopy. The shallow embedding depth of the particles on the eroded surface after SDA-WJP treatment led to difficult platelet formation for removal. The introduced refined grain hardening layer and CRS field were critical in preventing micro-crack initiation and propagation. This work optimizes the SDA-WJP process parameters for improving the surface integrity and SPE resistance of Ti-6Al-4V alloy, thus providing a reference for the application of SDA-WJP for the improvement of the SPE resistance of aero-engine blades. [Display omitted] • A novel SDA-WJP treatment is applied to improve erosion resistance. • The hardness, roughness, and residual stress of metal are improved after SDA-WJP. • The erosion resistance of Ti-6Al-4V alloy was improved up to 105 % after SDA-WJP. • Revealing the erosion mechanism of Ti-6Al-4V alloy after SDA-WJP treatment [ABSTRACT FROM AUTHOR]