In this study, thermal barrier coatings (TBC) consisting of 3.5 mol% Yb₂O₃-stabilized ZrO₂ co-doped with 1 mol% Gd₂O₃ and 1 mol% Yb₂O₃ (referred to as GdYb-YSZ) were fabricated by means of air plasma spraying. The as-fabricated coatings exhibited a metastable tetragonal (t′) structure. The hot-corrosion behavior of the GdYb–YSZ TBCs was investigated at 700, 800, 900, and 1000 °C for 10 h in the presence of V₂O₅ molten salt. During the corrosion tests, the t′ phase transformed into a monoclinic (m) phase; nevertheless, it was still detected on the corroded surfaces. The amount of t′ phase decreased with increasing corrosion temperature. The corrosion products formed on the GdYb-YSZ TBCs in V₂O₅ comprised Yb, Gd-doped YVO₄, and m-ZrO₂, irrespective of the temperature of corrosion. However, higher temperatures changed the morphologies of the Yb- and Gd-doped YVO₄ corrosion products. The GdYb–YSZ TBCs exhibited improved corrosion resistance to V₂O₅ molten salt when compared to YSZ TBCs, and the related mechanism is discussed in detail in this paper.

The work aims to study the change rule of the surface properties of aluminum (Al) alloy after shot peening (SP), and obtain the corresponding relationship between the surface material characteristics and SP parameters. Firstly, the Finite Element Model (FEM) of multi-projectile impact Al alloy specimen was established by ANSYS/LS-DYNA (Version: Ansys15.0). Box-Benhnken design method (BBD) was used to design 3-level and 3-factor shot peening experiment with shot peening pressure. Projectile size, jet distance, the surface residual stress, as well as deformation were taken as responses. The surface stress and the deformation at the crater were obtained according to the experiments. Then, Design-Expert software was adopted to fit the values to attain the multiple regression quadratic equations, and the response surface methodology (RSM) was applied to analyse the interaction between the various factors. The degree of model-fitting was simultaneously identified in accordance with an analysis of variance of the function models. Finally, the shot peening test was carried out using 7075-T651 Al alloy as the specimen. Combined with the X-ray diffraction (XRD) stress test and the optical microscopic observation of the crater section, the value of stress and deformation value could be determined to verify the accuracy of the model. The adjusted R² of the stress function model and the deformation function model were 94.85% and 95.08%, respectively. The deviation between calculated stress value and the experimental value was less than 5.5%. The deformation of the section showed that the deformed layer of the specimen was approximately the same as calculation value. The result indicated the function model had high accuracy. The analysis suggested that the function model could quickly and precisely deduce the parameter combination of the SP from the surface stress or deformation of the material, which provided a diversity reference for the surface stress and hardness strengthening of SP.

The Camellia oleifera fruit harvester, a specialized agricultural device, is engineered for efficient operation within the densely planted C. oleifera groves of China’s undulating terrains. Its design features a notably small footprint to navigate the constrained spaces between trees. With the enhancement of the functionality and power of the harvester, the engine compartment becomes even more congested. This, while beneficial for performance, complicates heat dissipation and reduces harvesting efficiency. In this study, experiments were initially conducted to collect temperature data from the main heat-generating components and parts susceptible to high temperatures within the harvester’s engine compartment. Subsequently, a 3D model was developed for numerical simulations, leading to the proposal of optimization schemes for the engine compartment’s structure and the validation of these schemes’ feasibility. A comparison of the experimental data, both before and after optimization, revealed a significant reduction in the surface temperatures of components within the engine compartment following optimization. As a result, the heat dissipation of the engine compartment has been greatly optimized. The harvester has demonstrated prolonged normal operation, enhancing the reliability and economy of the harvester.

BaNd₂Ti₃O₁₀ has been considered as a promising thermal barrier coating (TBC) candidate material, which reveals many advantages over the widely used TBC material of yttria partially stabilized zirconia, such as lower thermal conductivity, better high-temperature capability, and higher resistance to environmental deposits corrosion. In this study, the hot corrosion behavior of BaNd₂Ti₃O₁₀ in Na₂SO₄ + V₂O₅ molten salt at 900 °C and 1000 °C is investigated. Exposed to the salt for 4 h at 900 °C, BaNd₂Ti₃O₁₀ pellets had an obvious reaction with the salt, forming corrosion products of NdVO₄, TiO₂, and BaSO₄, and the reaction layer was ~30 μm, beneath which no salt trace could be found. Prolonging the corrosion time to 20 h, the type of the corrosion products had no change. At an elevated corrosion temperature of 1000 °C for 4 h, the corrosion products were still NdVO₄, TiO₂, and BaSO₄, but NdVO₄ revealed a significant growth, which fully covered the pellet surface. The mechanisms by which the corrosion reaction between BaNd₂Ti₃O₁₀ and the molten salt occurred were discussed.

This study explores the impact of shot peening residual compressive stress on repairing surface cracks in the 7075-T651 aluminum alloy. Two models were developed for crack repair via shot peening and fatigue test finite element modeling. A multi-step numerical simulation introduced shot peening-induced residual stress into the fatigue test model, and subsequent simulations analyzed the crack repair mechanism. The research results indicate that increasing pressure and projectile size improve repair effectiveness, but higher pressure causes material damage, and larger projectiles decrease fatigue life. Crack repair effectiveness decreased with higher loading levels, more significantly at higher loads. Experimental and simulation results matched well, validating the simulation model for shot peen repair processes and offering optimization possibilities.

Camellia oleifera harvester is a compact agricultural vehicle utilized in plantations located in China’s red soil hilly regions. To enhance its functionality and off-road performance, additional electronic devices and a more powerful powertrain system have been integrated within the engine compartment. However, the increased component density has resulted in constrained heat dissipation space, leading to critical issues including insufficient engine power, delayed control response, and reduced vibration frequency of the harvesting device. These thermal problems significantly compromise operational efficiency and pose safety hazards to operators. To address these heat dissipation challenges, this study proposes a collaborative optimization approach integrating computational fluid dynamics (CFD) simulation with an Adaptive Particle Swarm Optimization (APSO) algorithm. Initially, preliminary experiments, coupled with CFD simulations, were conducted to analyze the airflow distribution and temperature field within the engine compartment. Based on these findings, the component arrangement was reconfigured to improve thermal performance. Subsequently, an “engine compartment cover parameters–temperature” correlation model was established, and the dimensional parameters of the engine compartment cover were optimized using the APSO algorithm. Experimental results demonstrate that the optimized configuration achieves an average surface temperature reduction of approximately 17.82% for critical components, enabling prolonged stable operation and significantly enhanced operational reliability of the harvester.