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Non-conservative dislocation climb plays a unique role in the plastic deformation and creep of crystalline materials. Nevertheless, the underlying atomic-scale mechanisms of dislocation climb have not been explored by direct experimental observations. Here, we report atomic-scale observations of grain boundary (GB) dislocation climb in nanostructured Au during in situ straining at room temperature. The climb of a edge dislocation is found to occur by stress-induced reconstruction of two neighboring atomic columns at the edge of an extra half atomic plane in the dislocation core. This is different from the conventional belief of dislocation climb by destruction or construction of a single atomic column at the dislocation core. The atomic route of the dislocation climb we proposed is demonstrated to be energetically favorable by Monte Carlo simulations. Our in situ observations also reveal GB evolution through dislocation climb at room temperature, which suggests a means of controlling microstructures and properties of nanostructured metals. Dislocation climb is crucial to plasticity and creep of materials. Here, the authors report real-time atomic-scale observations of grain boundary dislocation climb in nanostructured Au at room temperature. The dislocation climb occurs by reconstruction of two atomic columns in the dislocation core.

Along with the globalization of environmental problems and the rapid development of the field of nuclear technologies, the severe irradiation damage of materials has become a big issue, restricting the development of advanced nuclear reactor systems. Refractory high-entropy alloys (RHEAs) have the characteristics of a complex composition, a short-range order, and lattice distortion and possess a high phase stability, outstanding mechanical properties, and excellent irradiation resistance at elevated temperatures; thus, they are expected to be promising candidates for advanced nuclear reactors. This review summarizes the design, preparation, and irradiation resistance of irradiation-tolerant RHEAs. It encompasses a comprehensive analysis of various aspects, including the evolution of defects, changes in microstructure, and the degradation in properties. Furthermore, the challenges and insufficiently researched areas regarding these alloys are identified and discussed. Building on this foundation, the review also provides a forward-looking perspective, outlining potential avenues for future research.

All‐solid‐sate Al‐air batteries with features of high theoretical energy density, low cost, and environmental‐friendliness are promising as power sources for next‐generation flexible and wearable electronics. However, the sluggish oxygen reduction reaction (ORR) and poor interfacial contact in air cathodes cause unsatisfied performance. Herein, a free‐standing Co3Fe7 nanoalloy and Co5.47N encapsulated in 3D nitrogen‐doped carbon foam (Co3Fe7@Co5.47N/NCF) is prepared as an additive‐free and integrated air cathode for flexible Al‐air batteries in both alkaline and neutral electrolytes. The Co3Fe7@Co5.47N/NCF outperforms commercial platinum/carbon (Pt/C) toward ORR with an onset potential of 1.02 V and a positive half‐wave potential of 0.92 V in an alkaline electrolyte (0.59 V in sodium chloride solution), which is ascribed to the unique interfacial structure between Co3Fe7 and Co5.47N supported by 3D N‐doped carbon foam to facilitate fast electron and mass transfer. The high ORR performance is also supported by in‐situ electrochemical Raman spectra and density functional theory calculation. Furthermore, the fabricated Al‐air battery displays good flexibility and delivers a power density of 199.6 mW cm−2, and the binder‐free and integrated cathode shows better discharge performance than the traditionally slurry casting cathode. This work demonstrates a facile and efficient approach to develop integrated air cathode for metal‐air batteries. A free‐standing Co3Fe7 and Co5.47N encapsulated in 3D N‐doped carbon foam (Co3Fe7@Co5.47N/NCF) is fabricated and served as an additive‐free and integrated air cathode for flexible Al‐air batteries in both alkaline and neutral electrolytes. The designed air cathode with faster mass and electron transfer demonstrates better battery performance than the traditional slurry casting cathode or commercial Pt/C cathode.

Rapid casting is the product of digital, information, and optimization of casting technology. It mainly includes rapid prototyping and virtual manufacturing. In order to shorten the production cycle of a stainless steel closed impeller casting, the wax pattern was made by high impact polystyrene (HIPS) with a selective laser sintering and photosensitive resin with stereolithography (SL). In order to prevent the formation of shrinkage defects, different gating systems designed to examine the molten metal flow and solidification behavior during the pouring and solidification process. The results show that pouring temperature is 1550 °C and pouring speed is 0.75 m/s, which is favorable for filling impeller castings, and can avoid casting defects. The optimized gating system prevented surface shrinkage and interior defects. The optimized gating systems have been verified by experiment, and the rapid casting has been realized based on 3D printing wax pattern and simulation optimization. This rapid casting can reduce processing time and costs, and enhance casting quality in the foundry industry.

Potential industrial applications of high-performance cast Al−Li−Cu−(Mg) alloys micro-alloyed with Sc have been strongly limited due to the extremely high production cost and scarcity of Sc. This work aimed at evaluating the effect of substituting Yb for Sc on the microstructure characteristics, age-hardening response and mechanical performances of cast Al−2Li−2Cu−0.5 Mg−0.2Zr alloy. Varied Yb additions were tried (0%, 0.1wt%, 0.2wt%) and results indicated that no appreciable grain refinement was achieved in alloys modified with Yb, accompanied with the absence of coarse primary phases. Dissolution of Cu-rich secondary phases during solution treatment was markedly retarded as the Yb addition increased to 0.2wt%. Nucleation of Al3Li on Al3(Yb, Zr) led to the significant reduction in the strain energy change (ΔGS) and interfacial energy. The addition of 0.1wt% Yb resulted in the accelerated age-hardening response and promoted precipitation of L12-structured nanometric core–shell Al3Li/Al3(Yb, Zr) precipitates, which acted as preferential nucleation sites for T1 and S′ phases. As a result, a better mechanical characteristics and microstructural stability was obtained in alloy with 0.1Yb addition compared with the base alloy. Moreover, as compared to the Sc-modified alloy, a small reduction in mechanical properties was achieved in 0.1Yb alloy accompanied with significant reduction in production cost, revealing the feasibility of substituting Yb for Sc.

The geometrical shape of the gating system and the casting process are vital to the occurrence of shrinkage porosity, and the effects of their combination directly determine the desired high-quality casting. Casting simulation plays a significant role in the deduction of the trial and error method for gating system design in investment casting, which is time-consuming. A breakthrough in optimization design often requires a comprehensive understanding of the geometrical structure of the gating system and the complex process parameter to generate a novel data-driven framework that improves the higher quality of casting and reduces the period of design. This paper proposed a data-driven framework to investigate the optimal gating system design integrated with complex casting processes through RBF optimization algorithm with the target of porosity-free casting as well as high casting yield percentage. The results demonstrate that the optimization of the gating design is more inspiring with high accuracy and high efficiency, and the casting yield is increased by 14.91%. Furthermore, the verification between simulation and experiments shows good agreement. The demonstrated data-driven approach is feasible and effective and can be extended not only incorporating the geometrical structure of the gating system and casting processes in investment casting optimization but also other potential types of casting design.

HighlightsA non-corrosive and air-stable hydrated eutectic electrolyte is developed.The electrolyte is composed of aluminum perchlorate nonahydrate and methylurea.The unique solvation structure enables reversible deposition/stripping of Al.The Al-ion battery in this electrolyte shows good charge/discharge performance.Aluminum-ion batteries (AIBs) have been highlighted as a potential alternative to lithium-ion batteries for large-scale energy storage due to the abundant reserve, light weight, low cost, and good safety of Al. However, the development of AIBs faces challenges due to the usage of AlCl3-based ionic liquid electrolytes, which are expensive, corrosive, and sensitive to humidity. Here, we develop a low-cost, non-corrosive, and air-stable hydrated eutectic electrolyte composed of aluminum perchlorate nonahydrate and methylurea (MU) ligand. Through optimizing the molar ratio to achieve the unique solvation structure, the formed Al(ClO4)3·9H2O/MU hydrated deep eutectic electrolyte (AMHEE) with an average coordination number of 2.4 can facilely realize stable and reversible deposition/stripping of Al. When combining with vanadium oxide nanorods positive electrode, the Al-ion full battery delivers a high discharge capacity of 320 mAh g−1 with good capacity retention. The unique solvation structure with a low desolvation energy of the AMHEE enables Al3+ insertion/extraction during charge/discharge processes, which is evidenced by in situ synchrotron radiation X-ray diffraction. This work opens a new pathway of developing low-cost, safe, environmentally friendly and high-performance electrolytes for practical and sustainable AIBs.

The influence of a static magnetic field on microstructure evolution during laser direct energy deposition was studied. Our results reveal that dendrite spacing increases with increasing magnetic field flux density (MFFD). Moreover, electron backscatter diffraction results reveal that the epitaxial growth was preferred with increasing MFFD. We discuss these findings in terms of the influence of a magnetic field on melt convection and propose that an applied magnetic field effectively limits Marangoni convection.

HighlightsFe single atoms supported on porous carbon nanofiber are prepared by spatial confinement.The iron single atoms supported on porous nitrogen-doped carbon nanofibers (FeSAs-NCF) can promote the reversible conversion between aluminum polysulfides.The FeSAs-NCF can chemically anchor the polysulfides to suppress shuttle effect.Rechargeable aluminum–sulfur (Al–S) batteries have been considered as a highly potential energy storage system owing to the high theoretical capacity, good safety, abundant natural reserves, and low cost of Al and S. However, the research progress of Al–S batteries is limited by the slow kinetics and shuttle effect of soluble polysulfides intermediates. Herein, an interconnected free-standing interlayer of iron single atoms supported on porous nitrogen-doped carbon nanofibers (FeSAs-NCF) on the separator is developed and used as both catalyst and chemical barrier for Al–S batteries. The atomically dispersed iron active sites (Fe–N4) are clearly identified by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption near-edge structure. The Al–S battery with the FeSAs-NCF shows an improved specific capacity of 780 mAh g−1 and enhanced cycle stability. As evidenced by experimental and theoretical results, the atomically dispersed iron active centers on the separator can chemically adsorb the polysulfides and accelerate reaction kinetics to inhibit the shuttle effect and promote the reversible conversion between aluminum polysulfides, thus improving the electrochemical performance of the Al–S battery. This work provides a new way that can not only promote the conversion of aluminum sulfides but also suppress the shuttle effect in Al–S batteries.

The dynamic behavior of ultrasound-induced cavitation bubbles and their effect on the fragmentation of dendritic grains of a solidifying succinonitrile 1 wt pct camphor organic transparent alloy have been studied experimentally using high-speed digital imaging and complementary numerical analysis of sound wave propagation, cavitation dynamics, and the velocity field in the vicinity of an imploding cavitation bubble. Real-time imaging and analysis revealed that the violent implosion of bubbles created local shock waves that could shatter dendrites nearby into small pieces in a few tens of milliseconds. These catastrophic events were effective in breaking up growing dendritic grains and creating abundant fragmented crystals that may act as embryonic grains; therefore, these events play an important role in grain refinement of metallurgical alloys.