Solid-state refrigeration technology is expected to replace conventional gas compression refrigeration technology because it is environmentally friendly and highly efficient. Among various solid-state magnetocaloric materials, Ni-Mn-based ferromagnetic shape memory alloys (SMAs) have attracted widespread attention due to their multifunctional properties, such as their magnetocaloric effect, elastocaloric effect, barocaloric effect, magnetoresistance, magnetic field-induced strain, etc. Recently, a series of in-depth studies on the thermal effects of Ni-Mn-based magnetic SMAs have been carried out, and numerous research results have been obtained. It has been found that poor toughness and cyclic stability greatly limit the practical application of magnetic SMAs in solid-state refrigeration. In this review, the influences of element doping, microstructure design, and the size effect on the strength and toughness of Ni-Mn-based ferromagnetic SMAs and their underlying mechanisms are systematically summarized. The pros and cons of different methods in enhancing the toughness of Ni-Mn-based SMAs are compared, and the unresolved issues are analyzed. The main research directions of Ni-Mn-based ferromagnetic SMAs are proposed and discussed, which are of scientific and technological significance and could promote the application of Ni-Mn-based ferromagnetic SMAs in various fields.
Key components in nuclear engineering serve as a security barrier, ensuring the smooth development of nuclear power technology, as well as safe and efficient operation of the nuclear power system in China. Metallic multilayers are novel nanostructured materials based on interface self-healing theory, which exhibit broad nuclear application due to their high-density heterogeneous interfaces. They can not only effectively hinder dislocation movement to enhance material strength but also obviously absorb irradiation-induced defects and promote their annihilation or recombination to improve material irradiation damage tolerance. Considering the recent domestic and international studies on irradiation characteristics of metal/high-entropy alloy multilayers, this study reviewed the evolution of microstructure and mechanical properties, and their underlying mechanisms in metal/high-entropy alloy multilayers before and after irradiation. Furthermore, it also explored strategies to enhance multilayers irradiation tolerance. The development of nanostructured multilayered materials with high tolerance to radiation damage were also proposed.
长余辉纳米粒子（persistent luminescence nanoparticles, PLNPs）是一种特殊的发光材料，具有很长的余辉时间。尤其是稀土元素（rare earth elements, REE）掺杂PLNPs（REE-PLNPs）具有独特的4f电子构型、优异的物理化学稳定性、高的发光强度和量子产率以及长的余辉时间。通过调节REE掺杂离子的种类和浓度，可以改变REE-PLNPs的发射波长范围。虽然发光中心相同，但由于不同材料所属的晶格不同，不同PLNPs基质材料的光学性质往往不同。因此，改变基质材料以及稀土共掺杂离子的种类，以提高REE-PLNPs的发光强度，进而可对余辉性能进行优化，故REE-PLNPs在室内装修、安全标志、仪表显示、生物检测和成像、诊疗一体化等领域受到了研究者的关注。以镧系元素和Sc与Y等掺杂REE-PLNPs为例，介绍了REE-PLNPs的组成和余辉发光性能及其在光学性质方面的研究进展。评述了REE在改善PLNPs的发射波长和余辉强度方面的优势，展望了REE-PLNPs研究未来的发展方向。
液体硅橡胶具有良好的化学稳定性和生物相容性,广泛应用于医疗及医疗器械领域,然而,在实际应用中存在机械支撑强度不足、稳定性不足以及易引发感染等缺陷.因此,提升液体硅橡胶的机械强度、抗菌性、化学稳定性和生物活性是首先要解决的问题.研究发现,将各种纳米填料添加到液体硅橡胶基质中,不仅可以提高材料的力学性能,还可以将其电学和抗菌性能提高到一个较好的水平.简要总结了液体硅橡胶的分类、构建及性能改进方式,重点阐述了液体硅橡胶在医学领域应用过程中的研究现状及目前所面临的瓶颈问题.液体硅橡胶生物医学功能改性研究有望提升纳米材料在液体硅橡胶中的分散性并改善其抗菌性、稳定性和导电性,提升液体硅橡胶的应用价值并拓展其应用场景.
The effect of Zr addition on microstructures and their evolution during heat treatments of a kind of Mg-Zn-Nd alloy was studied using various electron microscopy techniques. The minor addition of Zr not only provid heterogenous nucleation sites to refine grain sizes of Mg during solidification, but also influence microstructural evolution upon solution treatment and aging. Zn 2 Zr 3 precipitates were formed in Mg-2.7Nd-0.6Zn-0.5Zr（wt%） during solution treatment at 798 K, inducing remarkable hardness increment of the alloy. The atomic structure of nanometer Zn-Zr precipitates is determined by combining tilt series of micro-beam electron diffraction with atomic resolution imaging and chemical measurement. The stoichiometry of the Zn-Zr precipitates is Zn 2 Zr 3 with a primitive tetragonal structure（space group P4 2 /mnm, a=b=0.761 nm, c=0.682 nm）. Moreover, decrease in Zn concentration in Mg matrix due to the formation of Zn 2 Zr 3 precipitates increased the density ratio of β 1 -Mg 3 Nd prismatic rod precipitates to γ″-Mg 7 （Nd, Zn） 3 basal plates in peak aged samples. Our results may shed light on optimization of microstructures and mechanical properties of Mg alloys with Zr addition. Our present finding shed new light on the role of Zr micro-alloying in microstructures and mechanical properties of Mg alloys.
