九江职业技术学院

Advanced aero-engines with thrust-to-weight ratios of 15–20 require turbine blade materials (single-crystal superalloys) that can operate at temperatures of up to 1200 °C. However, the microstructural evolution of such superalloys is dominated by γ’ phase dissolution at 1200 °C. Here, the effect of γ’ phase dissolution on the microstructural characteristics and creep properties of superalloys at 1200 °C was investigated. Nine experimental Ni-based superalloys containing different γ’-forming elements, including Ta and Al, were prepared. The study showed that γ’ phase dissolution decreased the strength and elastic modulus of the γ matrix and increased its effective diffusion coefficient. The yield strength increment resulted from increased resistance to dislocation shear in the γ’ phase, which was enriched by Ta and Al. Moreover, the effect of γ’ phase dissolution on the strength of the γ’ phase was negligible. The formation of rattan-shaped structures and topological inversion of the γ–γ’ phases in Al- and Ta-rich alloys were instrumental in weakening the creep properties at 1200 °C. Finally, a creep property–microstructure control model that considers γ’ phase dissolution and excessive Ta and Al contents at 1200 °C was established; the values calculated using this model were consistent with the experimental observations. The findings of this study promote the design or selection of superalloys suitable for ultra-high-temperature applications.

The asymmetric creep aging behaviors of a pre-treated Al-Zn-Mg-Cu alloy under high and low stresses have been investigated for high precision creep age forming application of aluminum integral panels. With the increase of applied stress, the creep strains under the tensile stresses are higher than those of compressive stresses and the asymmetry of creep strain is more obvious. However, the mechanical properties of tensile stress creep aged samples are lower than those of compressive stress creep aged samples. Dislocation density, dislocation moving velocity and the proportion of precipitates directly lead to the asymmetry of creep strain and mechanical properties after tensile-compressive creep aging process. In addition, the tensile and compressive stresses have little effect on the width of the precipitate-free zone (PFZ). It indicates that in the high stress creep age forming process of the pretreated Al-Zn-Mg-Cu alloy, the tensile stress promotes the dislocation motion to obtain a better creep strain but weakens its mechanical properties compared with the compressive stress. In the field of civil aviation aircraft component manufacturing, the introduction of tension and compression stress asymmetry into the creep constitutive model may improve the accuracy of creep age forming components.

After a comprehensive review of oscillating heat pipe (OHP) based on battery thermal management system (BTMS), a novel battery liquid-cooling system with a ⊥-shaped OHP is presented to increase the volume utilization efficiency of battery module and the total amount of heat dissipation. The new system retains the heat transfer path of the OHP while incorporating an additional heat dissipation route where the liquid cooling plate is in direct contact with the cells. In this paper, pulsating flow is used to tackle the problem of the OHP failing to operate stably due to the insufficient heat load achieved in the new system. The parametric effects of pulsating flow frequencies, cooling initiation temperatures, and duty cycles on the operational performance of the OHP and the average surface temperature of the battery module (Tb) within the new system were investigated. The results indicate that pulsating flow periodically elevates the heat load on the battery surface, enhancing the OHP working properly. The smaller the pulsating flow frequency, the greater the impact on the temperature fluctuations of the new system. The Tb is lowest when the pulsating flow frequencies range from 0.03 Hz to 0.05 Hz. Beyond a frequency of 0.06 Hz, the OHP cannot operate stably. Additionally, moderately increasing the cooling initiation temperature is beneficial for enhancing the average temperature oscillation amplitude of the OHP. The cooling initiation temperature between 45 °C and 47 °C results in a better Tb. Both pulsating flow duty cycles of 38% and 62% contribute to OHP running effectively. The new system with OHP under optimum pulsating flow condition has the optimal Tb, eventually rising by 17.5 °C, which is a 9.8% decrease in temperature rise compared to the system without OHP. And the battery module's surface temperature uniformity has been improved through a reduction of 1.3 °C in the maximum temperature difference (ΔTmax), amounting to a 17.8% decrease. It has been proved that the improved thermal performance of the new system under pulsating flow is attributed to the stable operation of the OHP.

The dawn of Industry 4.0, characterized by the convergence of digital and physical technologies, ushers in a new era of economic and management paradigms. Blockchain technology, known for its decentralized, transparent, and immutable characteristics, is at the heart of this transformation. This paper explores the potential and challenges of integrating blockchain into Industry 4.0, focusing on economic and management innovations. Blockchain’s impact on sustainability reporting and corporate performance monitoring is profound, offering unprecedented transparency and trustworthiness. It enables granular insights into operations, fostering a responsible business ecosystem and equitable ecological accountability. However, aligning blockchain incentives with value-based objectives is crucial to avoid unintended consequences. Environmental concerns regarding blockchain’s energy consumption, especially in public blockchains like Bitcoin, highlight the need to balance innovation with ecological responsibility. Scalability remains a challenge, necessitating innovative solutions such as proof-of-stake. Furthermore, regulatory uncertainties and trust dynamics pose significant barriers to blockchain adoption. The paper emphasizes the importance of addressing these systemic challenges for the seamless integration of blockchain into economic and managerial ecosystems. Blockchain technology holds immense potential to revolutionize Industry 4.0 but comes with complexities and challenges. As industries, researchers, and policymakers navigate this uncharted territory, optimism, caution, and curiosity must guide their approach. Embracing blockchain’s transformative power while addressing its limitations can pave the way for a transparent, accountable, and sustainable future in Industry 4.0.

This article focused on the effect of ultrasonic surface rolling process (USRP) on the surface morphology, microstructure, microhardness and corrosion behavior of Mg-Gd-Zn-Zr alloy. Due to plastic deformation during USRP, the surface integrity of Mg-Gd-Zn-Zr alloy was reconstructed with the decrease of surface roughness, the introduction of grain refinement and twinning. It contributed to improve the microhardness and corrosion behavior that the surface microhardness increased about 25.5 % to 112.47 HV, and the corrosion current density decreased about 99.86 % to 1.362 x 10 -4 mu A/cm 2 . The results indicated that the USRP exhibited good application prospects in improving the surface properties of Mg alloys.