The highly alloyed Mg-10Gd-5Y-5Er alloy exhibits high strength, however, the brittle Mg₂₄RE₅ phase accelerates the initiation and development of micro-cracks and significantly deteriorate the plastic deformation ability. Therefore, it is necessary to regulate the type of precipitates to improve the comprehensive mechanical properties of the alloy. In this work, the influence of Zn content on mechanical properties and microstructure evolution of highly alloyed Mg-10Gd-5Y-5Er-xZn alloys (x = 0, 1, 2, 3, and 5 wt%) was investigated. It was found that the tensile strength increases with increasing Zn content, without deterioration of elongation. The maximum tensile yield strength and ultimate tensile strength are achieved to be 298 MPa and 406 MPa, respectively, within the studied concentration range. Thermodynamic calculations and microstructural characterization results indicate that with the increase of Zn content the precipitate transform from Mg₂₄RE₅ phase to long-period-stacking-ordered (LPSO) phase and lamellar structure. This transition will change the solute atom concentration in the matrix and affect the dynamic recrystallization behavior, thereby changing the contributions of solid solution strengthening and grain refinement strengthening to the yield strength of alloy. In particular, the blocky LPSO phase can significantly contribute to the increased strength at relatively high Zn contents (x > 2 wt%) by a mechanism similar to short-fiber strengthening. Moreover, the strategy of improving the mechanical properties by increasing the volume fraction of blocky LPSO phase can be applied to many Mg alloy systems containing LPSO phase.

Dislocation loop is a primary indicator of irradiation, and has a profound impact on the microstructural evolution and thermo-mechanical properties of materials. Although both 1/2<111> and <100> loops are clearly identified in bcc metals after irradiation, the underlying mechanism of <100> loop formation remains elusive especially considering its low stability. Here, we explicitly demonstrate the formation of <100> loops through the interaction of two gliding 1/2<111> loops under uniaxial strain via molecular dynamics simulations, while there is no occurrence of <100> loops under strain-free conditions. Such strain-enhanced formation of <100> loops is different from conventional dislocation reaction mechanisms, which contain rigorous prerequisite conditions on the topology and size of the reactant loops, and thus provide a potential explanation for the frequent occurrence of<100> loops. The microscopic analysis suggests that the generation of <100> dislocation loops via bi-loop reaction is a complicated atomistic process involving the coordinated movement and/or rearrangement of multiple interstitials. The activation energy barriers of each reaction step are determined, and generally decrease with increasing uniaxial strain. Specifically, we develop a predictive model to describe the formation probability of<100> loops under different conditions, which is in good agreement with molecular dynamics simulations. These results shed new light on understanding the <100> loop formation, provide a direct link between simulations and experiments, and enable the accurate assessment of irradiation damage evolution in bcc metals.

Liquid crystal polymers (LCPs) combine the entropic elasticity of polymers with the orderness of LC mesogens, demonstrating outstanding performance across diverse applications, particularly in bionic actuators. In contrast to the organisms that enable multi-stimuli responsibility, most LCP actuators reported thus far exhibit responsiveness to only a single stimulus, hence the fabrication of multi-stimuli responsive LCPs is of pronounced significance. Here, a novel multi-stimuli responsive LCP is developed by integrating ring-opening metathesis polymerization (ROMP) and post-polymerization modification (PPM), which exhibits reversible responsiveness to humidity, light, and pH. By spray-coating the stretched polypropylene with LCP, the bilayer actuator loads exceed 20 times its weight upon exposure to light irradiation and moisture, showcasing exceptional output force. Furthermore, in response to the change in pH and humidity, the actuator exhibits behaviors akin to natural flowers, including blooming, closing, and color-changing. The strategy combining ROMP and PPM has proven to be a versatile strategy for the synthesis of multifunctional LCPs, offering transformative potential for the development of advanced bionic actuators and soft robotic systems.

Two-dimensional transition metal carbides (MXenes) have garnered significant attention due to their distinctive physical and chemical properties. In this study, utilizing density functional theory calculations, we introduce a novel phase of transition metal carbide with the space group of R3m, designated as α-MXene with the chemical formula M₂CX₂ (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn; X = O, F). Notably, α-MXene possesses an ABBCA atomic layer configuration closely resembles the two-dimensional ferroelectric material α-In₂Se₃, distinct from the close packing ABCAB atomic stacking observed in typical MXenes. It is highlighted that α-MXene exhibits adjustable ferroelectric properties with moderate polarization reversal energy barriers, including five rare ferroelectric metals and one Dirac-semimetal. Moreover, α-MXenes not only enable photocatalytic reactions by utilizing infrared light to overcome the band gap restriction of 1.23 eV, but also generate hydrogen and oxygen gases on separate surfaces due to electric field induced by ferroelectric effect. Additionally, ferroelectric tunnel junctions (FTJs) based on α-MXene show exceptionally high tunneling electroresistance ratios (TERs), indicating their suitability for advanced ferroelectric memory device applications. Our research provides a viable strategy for exploring ferroelectric materials within the expansive MXene family and exemplifies the applications of α-MXenes in photocatalysis and spintronics.