Molecular dynamics simulations of compression deformation of $\left[ {11\bar 20} \right]$ -textured 2-dimensional polycrystalline pure Mg, Mg–0.1 at.%Al, and Mg–1.0 at.%Al models were performed at 5 and 300 K. A $\left\{ {10\bar 11} \right\}$ twin nucleated before formation of a $\left\{ {10\bar 12} \right\}$ twin in the simulations at 5 K, while a $\left\{ {10\bar 11} \right\}$ twin nucleated after formation of a $\left\{ {10\bar 12} \right\}$ twin in the simulations at 300 K. The formation of a $\left\{ {10\bar 11} \right\}$ twin was the result of the glide of pyramidal 〈c + a〉 partial dislocations of ${1 \mathord{\left/ {\vphantom {1 6}} \right. \kern-\nulldelimiterspace} 6}\left\{ {10\bar 11} \right\}\left[ {\bar 2023} \right]$ . $\left\{ {10\bar 11} \right\}$ twin formation was suppressed at the sites around the Al atoms because the strong Mg–Al bond suppresses atomic shuffling. However, formation was not suppressed at the sites away from the Al atoms because the effect of strong Mg–Al bond is short range. On the other hand, because $\left\{ {10\bar 12} \right\}$ twinning requires the simultaneous glide of zonal dislocations, Al inevitably suppressed $\left\{ {10\bar 12} \right\}$ twinning.

This study modified the surfaces of three kinds of TiNi-based shape memory alloys (SMAs) by dry electrical discharge machining (EDM) in nitrogen (N2) and acetylene (C2H2) gas mixture. The effects of composition of the dielectric medium and work-piece on the machining performance and surface characteristics were investigated. Increasing the ratio of acetylene gas in gas mixture was beneficial for improving the material removal rate (MRR). However, adding a large amount of acetylene gas resulted in unstable discharge. A recast layer, comprising nitrides and carbides, which well adhered on the EDMed surface exhibited high hardness. Among Ti50Ni50, Ti50Ni49.5Cr0.5, and Ti40.5Ni49.5Zr10 SMA as a work-piece, Ti40.5Ni49.5Zr10 SMA has the lowest MRR owing to it possessed the highest melting temperature and thermal conductivity. The recast layer on Ti40.5Ni49.5Zr10 SMA, comprising zirconium nitride, exhibited the highest hardness and adhesion among all the SMAs. However, the high-hardness recast layer deteriorated the shape recovery of the SMA.

Density functional theory computations were performed to investigate the adsorption and diffusion properties of lithium (Li) on tin disulfides nanosheets and its derived nanoribbons (NRs), in comparison with SnS2 bulk in 1T phase. The Li adsorption energies and migration barriers are comparable in SnS2 bulk and bilayer, and Li adsorbed at the octahedral sites has the highest binding energy in both SnS2 bulk and bilayer. Reducing the dimension of SnS2 to monolayer significantly lowers the Li diffusion barrier while keeping a considerable binding energy, and lithium favors the hollow sites which corresponding to the octahedral sites in bulk phase. Due to the edge effect, SnS2NRs gain an enhanced Li binding strength, increased Li mobility, and improved Li capacity. Thus, SnS2 NRs are a promising candidate for anode materials of Li-ion batteries with a high power density and fast charge/discharge rates.

Silicone Rubber (SR) filled with graphene nanoplatelets (GNPs) and carbon black (CB) is prepared for high performance flexible pressure sensor. Due to the synergetic effect of mixed GNPs and CB, the percolation threshold of GNPs/CB/SR is lower than that of CB/SR, which indicates the addition of GNPs is contributed to enhance the electrical conductivity of GNPs/CB/SR. Moreover, the GNPs/CB/SR has a higher electrical stability and weaker resistance creep than that of GNPs/SR. That is to say, the addition of CB can promote the electrical and mechanical performance of GNPs/CB/SR, simultaneously. The pressure sensor array based on GNPs/CB/SR with weight on different sensing element is tested, and the results show that the size of applied loading on the pressure-sensitivity array can be recognized accurately.

Powders of BaSnO3 were synthesized to obtain gas sensor thick films (using the screen printing technique) for the detection of O2 and CO. Impedance spectroscopy was used at different atmospheres and temperatures. In the presence of O2, the films showed a maximum value of sensitivity at 300 °C, with the powders formed by Pechini presenting greater reproducibility and sensitivity (with an order of magnitude greater than that for the powders formed by precipitation). Results showed that the films formed with powders obtained using the Pechini method presented a better response to CO, with a maximum sensitivity at 450 °C. In addition, in the presence of CO and for T > 250 °C, these films showed an anomalous behavior regarding their sensitivity as a function of time when platinum electrodes were used: a great increase in the electrical resistance value for exposure times greater than 10 min.

Disks of commercial Al-1050 and ZK60A alloys were stacked together and then processed by conventional high-pressure torsion (HPT) through 1 and 5 turns at room temperature to investigate the synthesis of an Al–Mg alloy system. Measurements of microhardness and observations of the microstructures and local compositions after processing through 5 turns revealed the formation of an ultrafine multi-layered structure in the central region of the disk but with an intermetallic β-Al3Mg2 phase in the form of nano-layers in the nanostructured Al matrix near the edge of the disk. The activation energy for diffusion bonding of the Al and Mg phases was estimated and it is shown that this value is low and consistent with surface diffusion due to the very high density of vacancy-type defects introduced by HPT processing. The results demonstrate a significant potential for making use of HPT processing in the preparation of new alloy systems.

Superconductivity and magnetism at intermediate (“mesoscopic”) length scales between atomic and bulk have a long history of interesting science. New science emerges due to the presence of multiple length scales, especially when these become comparable to relevant geometric sizes. New phenomena may appear due to topological interactions, geometric confinement, proximity between dissimilar materials, dimensional crossover, and collective effects induced by periodicity. In this review, we select a few, recent highlights that illustrate the type of novel science that can be accomplished in superconducting and magnetic structures. These materials can serve as model systems and provide new ideas, which can be extended to other systems such as ferroelectrics and multiferroics. We also highlight general open questions and new directions in which the field may move.

The ability to pattern materials in three dimensions is crucial for structural, optical, electronic, and energy applications. Three-dimensional printing allows one to design and rapidly fabricate materials in complex shapes without the need for expensive tooling, dies, or lithographic masks. A growing palette of printable materials, coupled with the ability to programmably control mesoscale architecture, open new avenues for creating designer materials with unprecedented performance.

Self-assembled epitaxial oxide composite films represent a new material form in which very high-quality mesoscopic structures can be created. The main focus has been on coupled electronic devices, but so far, only a very narrow range of compositions and structure types have been explored. Insufficient attention has been paid to the very wide window of possible materials combinations or to the novel materials properties that could be induced. Both of these aspects need to be addressed before we attain mesoscale devices with new properties. In this article, we review the unique materials properties of these epitaxially directed mesoscale composite structures, discussing their very high crystallinity, structural uniformity, and orientation. We also review how the structures can be size-tuned, from ∼2 nm up to ∼50 nm, and how they can be spatially ordered. We discuss how unusual strain states can be induced in the structures, and how epitaxial stabilization of the mesoscale surfaces within the films eliminates problems of surface degradation inherent to “free” nano/mesostructures. Several exemplar systems are given to show that composite films represent an unrivaled new approach to engineering new properties into mesoscale systems.