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As 5G communication technology allows for speedier access to extended information and knowledge, a more sophisticated human-machine interface beyond touchscreens and keyboards is necessary to improve the communication bandwidth and overcome the interfacing barrier. However, the full extent of human interaction beyond operation dexterity, spatial awareness, sensory feedback, and collaborative capability to be replicated completely remains a challenge. Here, we demonstrate a hybrid-flexible wearable system, consisting of simple bimodal capacitive sensors and a customized low power interface circuit integrated with machine learning algorithms, to accurately recognize complex gestures. The 16 channel sensor array extracts spatial and temporal information of the finger movement (deformation) and hand location (proximity) simultaneously. Using machine learning, over 99 and 91% accuracy are achieved for user-independent static and dynamic gesture recognition, respectively. Our approach proves that an extremely simple bimodal sensing platform that identifies local interactions and perceives spatial context concurrently, is crucial in the field of sign communication, remote robotics, and smart manufacturing.

Refractory alloys such as tungsten and molybdenum based alloys with high strength, thermal/electrical conductivity, low coefficient of thermal expansion and excellent creep resistances are highly desirable for applications in nuclear facilities, critical components in aerospace and defense components. However, the serious embrittlement limits the engineering usability of some refractory alloys. A lot of research results indicate that the performances of refractory alloys are closely related to the physical/chemical status, such as the interface dimension, interface type, interface composition of their grain boundaries (GBs), phase boundaries (PBs) and other interface features. This paper reviewed the recent progress of simulations and experiments on interface design strategies that achieve high performance refractory alloys. These strategies include GB interface purifying/strengthening, PB interface strengthening and PB/GB synergistic strengthening. Great details are provided on the design/fabrication strategy such as GB interface controlling, PB interface controlling and synergistic control of multi-scaled interfaces. The corresponding performances such as the mechanical property, thermal conductivity, thermal load resistance, thermal stability, irradiation resistance, and oxidation resistance are reviewed in the aspect to the effect of interfaces. In addition, the relationships between these interfaces and material properties are discussed. Finally, future developments and potential new research directions for refractory alloys are proposed.

We report on a room temperature Aerosol Jet printed two-terminal WSe2 crossbar architecture device on flexible substrate that achieves dual functionality of both a resistive random access memory (ReRAM), as well as a photosensor. As a ReRAM, the silver contacted WSe2 device exhibits forming free, sub 1-V switching voltage, and an on-off ratio of 2 orders. Furthermore, the WSe2 ReRAM exhibits both volatile and non-volatile switching behavior with a transition set current of ${2}~\mu \text{A}$ , translating to a low operating power of ${16}~\mu \text{W}$ . As a photosensor with the same architecture, the transparent CNT electrodes contacted device allows incident light to pass through for photocurrent generation. The two terminals device allows photo sensitivity to be tuned by bias application. In such mode, a maximum photo responsivity of 1 A/W at a visible light wavelength of 660 nm is exhibited by the device at a bias of 1 V, allowing weak light signals to be amplified. In both cases, the WSe2 device retains its functionality even after bending down to a radius of 5 cm. The fabrication process can be up-scaled and has great potential to be used for conformal electronics system integration.

3D monolithic integration of logic and memory has been the most sought after solution to surpass the Von Neumann bottleneck, for which a low-temperature processed material system becomes inevitable. Two-dimensional materials, with their excellent electrical properties and low thermal budget are potential candidates. Here, we demonstrate a low-temperature hybrid co-integration of one-transistor-one-resistor memory cell, comprising a surface functionalized 2D WSe2 p-FET, with a solution-processed WSe2 Resistive Random Access Memory. The employed plasma oxidation technique results in a low Schottky barrier height of 25 meV with a mobility of 230 cm2 V−1 s−1, leading to a 100x performance enhanced WSe2 p-FET, while the defective WSe2 Resistive Random Access Memory exhibits a switching energy of 2.6 pJ per bit. Furthermore, guided by our device-circuit modelling, we propose vertically stacked channel FETs for high-density sub-0.01 μm2 memory cells, offering a new beyond-Si solution to enable 3-D embedded memories for future computing systems. Designing efficient, scalable and low-thermal-budget 2D Materials for 3D integration remains a challenge. Here, the authors report the development of a hybrid-(solution-processed-exfoliated) integration of 2D Material based 1T1R which uses a multilayer WSe2 p-FET and a multilayer printed WSe2 RRAM.

Bulk W-0.5 wt% ZrC (WZC) plates were fabricated using tungsten powders with different powder grain sizes of 0.2 μm, 0.5 μm and 2.8 μm, respectively. The different grain sizes resulted in completely different micro-structures and mechanical properties of as-rolled WZC plates. For the tungsten plate prepared from the initial powder with grain size of 0.5 μm (0.5WZC), more excellent mechanical properties were achieved than those of plates made of powders with grain sizes of 0.2 μm (0.2WZC) and 2.8 μm (2.8WZC). In the as-rolled 0.5WZC, the ductile-brittle transition temperature is as low as 150 °C and ultimate tensile strength is as high as 932 MPa at 150 °C, respectively. Moreover, the 0.5WZC plate has the most outstanding high-temperature stability with a recrystallization temperature of 1500 °C. Micro-structure analysis indicates that the second-phase particles are uniformly distributed in the 0.5WZC, but serious particle aggregation occur in the 2.8WZC. The possible micro-mechanisms have been proposed.

Monoculture and rotation systems usually exhibit distinct diversity and composition of microbial community in the cultivation of various plants, but the network structures and keystone species of microbial communities in these two cropping systems are poorly understood. To better understand this issue, we constructed four ecological networks of bacterial communities in bulk and rhizosphere soils of soybean grown in the two cropping systems, i.e. continuous cropping of soybean (CC) and acropping rotation with maize (CR), using Molecular Ecological Network Analysis Pipeline (MENAP). The results revealed that the bacterial network structure and composition between the two cropping systems in both bulk and rhizosphere soils were greatly different, with larger differences between CC and CR in rhizosphere soils than in bulk soils. Compared with CC, CR increased the stability and complexity of bacterial networks in both bulk and rhizosphere soils. Predominantly positive (> 75%) correlations in all the networks indicated that extensive cooperative interactions occurred among bacterial taxa in Mollisols. Putative keystone species that typically had low relative abundance performed distinct ecological functions in the two cropping systems. These results provide new insights into the bacterial interactions and ecological function in continuous cropping and crop rotation systems.

Fe-Ga alloys exhibit unique functional properties such as magnetostriction and high damping that can be adjusted by the phase transitions (D03 to L12) through a proper compositions and heat treatments. In this paper, the effect of phase composition on the internal friction (IF) and magnetostriction in Fe-27Ga alloys were systematically investigated. It was found that proportion of L12 phase in the biphase (L12/D03) Fe-27Ga alloys can be controlled by adjusting the annealing temperature and holding time. Two temperature-dependent IF peaks, i.e., a Snoek-type relaxation peak (P1) associated with the stress-induced jump of interstitial C atoms in the bcc-derived D03 phase and a Zener-type relaxation peak (P2) associated with stress-induced jump of Ga-pairs in the D03 phase were observed. The height of both peaks decreases gradually with the increasing content of L12 phase. The absolute value of magnetostriction at an applied magnetic field higher than 2000 Oe and the amplitude-dependent IF at a strain amplitude up to 10-3 decreases at first and then increases with the increasing content of L12 phase. With the increasing strain amplitude, magneto-mechanical damping of D03 phase increases at first and then decreases, while that of the L12 phase increases monotonously. This indicates that the magnetic domain walls of D03 phase can move easily under a low stress, while those of L12 phase can be driven only when the stress is high enough. Such researches could provide a design concept for high damping Fe-Ga alloys to meet the requirements in different application fields such as micro-vibration field, strong vibration field, magnetic or non-magnetic field.

Repetitive thermal loads inducing damage behaviors of ITER grade tungsten (W) have been investigated using an electron beam device EBMP-30. The metallographic observation, backscattered electron scanning electron microscopy, electron backscattered diffraction, atomic force microscopy analysis and tensile tests were carried out after the repetitive heat loads. Results indicate that there are negligible effects on the microstructures, surface morphologies and mechanical properties with the absorbed power densities (APD) lower than 10 MW/m2. While serious damages including the severe surface roughness with protruding structures along grain boundaries, and significant grains coarsening with the evolution of the grain shape occur undesirably due to the full recrystallization during the repetitive 30 MW/m2 heat loads. Furthermore, after exposed to an APD of 30 MW/m2 with 50 heat loads, the tensile properties deteriorate dramatically, resulting in a limited ultimate tensile strength of only 328 MPa and even a zero total elongation at 300 °C. The relationships between the thermal loads, microstructures evolution and degradation of mechanical properties have been analyzed.

To improve microstructure and fracture toughness of MASC alloy, the effects of element substitution of Zr for Hf on the microstructure and room-temperature fracture toughness in Nb-24.7Ti-16Si-xHf-yZr-2.0Cr-1.9Al (x + y = 8.2) alloys have been investigated in this study. The results show that the substitution of Zr for Hf in MASC alloy promotes the eutectic reaction of (Nb, X)3Si phase → Nbss/γ(Nb, X)5Si3 eutectic, and shifts the eutectic point to higher Si content, which leads the microstructure transformation from hypereutectic structure to nearly eutectic structure. The primary γ(Nb, X)5Si3 phase content decreases and Nbss phase content increases with the increase of Zr content. The room-temperature fracture toughness increases with the increase of Zr content, and the room-temperature fracture toughness values of 4Zr-4.2Hf, 6Zr-2.2Hf and 8.2Zr-0Hf alloys are 16.03–16.29 MPa m1/2. The room-temperature fracture toughness value of 16.29 MPa m1/2 is the highest value in the nondirectionally solidified Nb-Si based alloys.

This paper deals with microstructural evolutions, phase constitutions and fracture toughness of Nb–16Si–22Ti-(6Mo/8Cr/2W) alloys using the vacuum non-consumable arc-melting. The results show that the addition of 6 at.% Mo or 8 at.% Cr promotes the eutectic reaction of (Nb, X)3Si phase → Nbss/(Nb, X)5Si3 eutectic. The common addition of 8 at.% Cr and 6 at.% Mo leads to the microstructure transform from hypoeutectic microstructure to near-eutectic microstructure. The Nb–16Si–22Ti–8Cr alloy with coupled structure of Nbss/(Nb, X)5Si3 eutectic has the maximum fracture toughness of 13.4 MPa m1/2. The 6 at.% Mo or 2 at.% W addition has little influence on the room-temperature fracture toughness KQ value, but the common addition of 8 at.% Cr, 6 at.% Mo and 2 at.% W can improve room-temperature fracture toughness KQ value. The high content of Nbss phase and Nbss dendritic crystal in the matrix can contribute to fracture toughness of NbSi alloy. The coupled structure of Nbss/(Nb, X)5Si3 eutectic can prevent the crack propagation and improve the fracture toughness.

Bulk nanolayered Cu/V composites simultaneously exhibit high strength and outstanding thermal stability due to its unusually high density of interfaces. However, investigation of the irradiation stability of this material is still in its infancy, limiting further application of these materials under radiation conditions. Herein we investigated the radiation response of bulk nanolayered Cu/V composites exposed to 200 keV He ions with two irradiation fluences of 2 × 1021 ions/m2 and 7 × 1022 ions/m2. It is demonstrated that the bulk Cu/V nanolayered composites remained stable with respect to mechanical property and microstructure after irradiation with fluence of 2 × 1021 ions/m2. In contrast, for materials exposed to high irradiation fluence of 7 × 1022 ions/m2, severe irradiation damage, such as obvious surface blistering, elongated He voids, and layer morphological instability, were developed. In addition, asymmetric He bubbles distribution and obvious He bubble-free zones were observed near the Cu/V interfaces and within layers. The mechanisms of radiation-induced instabilities and He bubbles formation are discussed in detail.

High damping capacity and low density M2052/Al composites were successfully fabricated using the accumulative roll bonding (ARB) method, by taking advantages of high damping capacity for M2052 alloy (Mn-20Cu-5Ni-2Fe, at%) particles and excellent mechanical properties and low density for Al matrix. The 15 wt% M2052 particles were uniformly dispersed in Al-matrix after 10 ARB process cycles. M2052/Al composites have a low density of 2.9 g/cm3, which is just a little higher than that of Al. After ARB process and a subsequent hydrogen annealing, the M2052/Al composites exhibit both high room temperature damping capacity and good mechanical properties: the highest damping capacity is 0.01 at 270 K, 5 times that of pure Al at the comparative temperature; the ultimate tensile strength is about 70 MPa (about 35% higher than that of pure Al), and the total elongation reaches 24%. The simultaneous enhancements on damping capacity and tensile strength of the M2052/Al composites can be attributed to the high damping capacity and the dispersion strengthening of M2052 phase, as well as the good bonding between the M2052 particles and Al matrix resulted from the ARB technique.

Annealing of a tungsten alloy containing 0.5 wt% zirconium carbide (WZC) in hydrogen atmosphere induced hydrogen embrittlement, which was investigated by exploring the evolution of the tungsten grain size and orientation, the second phase particles distribution, and the tensile properties of the hydrogen-containing and hydrogen-free WZC samples. Thermal desorption spectroscopy used to determine the hydrogen retention revealed a broad hydrogen desorption peak at 1000 – 1300 K, whose hydrogen origin was attributed to the trapping sites in the non-stoichiometric ZrCx of the WZC samples after annealing in hydrogen atmosphere at 1300 °C. Hydrogen retention resulted in the degradation of mechanical properties including strength and ductility and in the deterioration of the ductile-to-brittle-transition behavior. The results emphasize the importance of the atmosphere choice for annealing tungsten materials to avoid hydrogen embrittlement and to ensure good mechanical properties.

An ultrafine ZrC nanoparticles dispersion strengthened sub-micrometer grained W-0.5 wt% ZrC alloy (W-ZrC) were fabricated by an improved ball milling and spark plasma sintering (SPS) process. The as prepared W-ZrC has an average grain size of ∼0.86 μm with an average second-phase particle size of 24 nm. The thermal stability and thermal shock resistance of this W-ZrC alloy were investigated systemically by comparison with the reported rolled specimens. For this W-ZrC alloy, the evolution of microstructure with annealing temperature indicates that the occurrence temperature of grain growth is up to 1400 °C–1500 °C, which is higher than that of the as-rolled one (∼1350 °C). Moreover, the crack threshold (100 shots) at room temperature is in the range of 0.22−0.33 GW/m2, which is similar to that of most carbide dispersion strengthening tungsten alloys. In addition, a quantitative relationship between Vickers micro-hardness and grain size of sintered W-based alloys has been proposed.

Recrystallization and thermal shock fatigue resistance behavior of nanoscale ZrC dispersion strengthened bulk tungsten alloys (W-0.5 wt% ZrC, WZrC) as potential candidates for plasma-facing components were investigated. By employing heat treatments with isochronal experiments, the evolution of the tungsten grain size/orientation, second phase particle distribution, thermal conductivity and mechanical properties were systematically studied. The effects of edge-localized mode like transient heat events on the as-rolled and recrystallized WZrC were investigated carefully. Pulses from an electron beam with durations of 1 ms were used to simulate the transient heat loading in fusion devices. The cracking thresholds, cracking mechanisms and recrystallization under repetitive (100 shots) transient heat loads were investigated. Results indicate that the cracking threshold of all the WZrC samples is 220–330 MW/m 2 (corresponding to a heat load parameter F = 7.0–10.4 MJ/m 2 s 1/2 ) at room temperature and the heat bombardment induced recrystallization occurs at a heat parameter of 10.4 MJ/m 2 s 1/2 .

In this paper, W-0.5 wt.% Ta-0.01 wt.% C (W-05Ta-001C) alloys were fabricated via a combination of high energy ball milling and subsequent spark plasma sintering. The W-05Ta-001C alloys showed high strength of 565 MPa at 400 °C with a total elongation of 54%. The improved ductility resulted from nanosized TaC precipitation. The microstructure analysis of W-05Ta-001C alloys indicate that the nanosized TaC precipitation uniformly distributed in the grain interior encouraging trapping dislocations. TaC could reduce free oxygen concentration and thus enhance grain boundaries strength by reacting with impurities of oxygen to form compounds of Ta-Cx-Oy at grain boundaries. The thermal stability of W-05Ta-001C alloys was investigated by analyzing the evolution of hardness based on isochronal annealing tests. The results showed that hardness only slightly decreased with increasing annealing temperature up to 1500 °C, and the recrystallization temperature was about 1600 °C. This good thermal stability is attributed to nanosized TaC dispersion strengthened structures.

The well-known Maillard reaction in milk occurs between lactose and milk proteins during thermal treatment, and its effects on milk nutrition and safety have been well studied. A lactose-glycated caseinate was prepared via this reaction and digested using 2 digestive proteases, pepsin and trypsin. The glycated caseinate digest was assessed for its in vitro activities on rat intestinal epithelial cells in terms of growth proliferation, anti-apoptotic effect, and differentiation induction using caseinate digest as reference, to verify potential effects of the Maillard reaction on these activities of caseinate digest to the cells. Two digests had proliferative and anti-apoptotic effects, and reached the highest effects at 0.02 g/L of digest concentration with treatment time of 24 h. In comparison with caseinate digest, glycated caseinate digest always showed weaker proliferative (5.3-14.2%) and anti-apoptotic (5.9-39.0%) effects, and was more toxic to the cells at 0.5 g/L of digest concentration with treatment time of 48 h. However, glycated caseinate digest at 2 incubation times of 4 to 7 d showed differentiation induction higher than caseinate digest, as it could confer the cells with increased activities in lactase (16.3-26.6%), sucrase (22.4-31.2%), and alkaline phosphatase (17.4-24.8%). Transmission electron microscopy observation results also confirmed higher differentiation induction of glycated caseinate digest. Amino acid loss and lactose glycation partially contributed to these decreased and enhanced activities of glycated caseinate digest, respectively. The Maillard reaction of caseinate and lactose is thus shown in this study to have effects on the activities of caseinate digest to intestinal epithelial cells.

The cubic Ca/Ta-substituted Li6.55(La2.95Ca0.05)(Zr1.5Ta0.5)O12 (LLCZTO) electrolytes were synthesized at 800 °C with Li3BO3 as additives. The optimal amount of Li3BO3 and its influences on the microstructure, crystal structures, Li+ conductivity and the stability of the Li6.55(La2.95Ca0.05)(Zr1.5Ta0.5)O12 were studied by SEM, XRD and EIS. Among all the samples, when the molar ratio of Li3BO3 to the Li6.55(La2.95Ca0.05)(Zr1.5Ta0.5)O12 is 4:5, the highest Li+ conductivity of 1.33 × 10−4 S cm−1 at 30 °C is obtained. When the LLCZTO samples are exposed in air, the Li+ conductivity is deteriorated possibly owing to the side reactions between the LLCZTO and the H2O or CO2 in the air. The Li3BO3 addition can alleviate such deterioration of the Li+ conductivity.

The feasibility and toughening efficiency of the short tungsten fibre reinforcement on tungsten were investigated in W f /W composites fabricated by powder metallurgy method of spark plasma sintering. Fibres in the composites presented a Z-free laminar structure. Partial recrystallization of fibre grains occurred but fibre crack or damage was not detected. Fracture energy of W f /W composites was estimated in tensile tests, and the results indicated great toughness improvement over pure tungsten in virtue of frictional pullout and plastic deformation of fibres, and matrix-fibres interfacial debonding since 873 K. The specimen with mass fraction of 10% and fibre diameter of 100 µm exhibits the largest elongation of 9±1.1% and the highest ultimate strength of 482±13 MPa at 873 K.

In order to fabricate high damping/strength metal matrix composites, hard ceramic particulates Li 6.75 La 3 Zr 1.75 Nb 0.25 O 12 (LLZNO) reinforced Al composites were prepared by accumulative roll bonding (ARB) method with intermittent heat treatments. LLZNO particles did not react with Al and were uniformly dispersed in Al-matrix after 10 ARB cycles. With increasing ARB cycles, the ultimate tensile strength of the LLZNO/Al composites increased and reached 132 MPa after 10 ARB cycles, which was 2.5 times that of the pure Al, while the total elongation of LLZNO/Al composites increased from 5% after 1 cycle to 10% after 10 cycles. The maximum damping capacity as high as 0.009 was achieved after 10 ARB cycles in the 10 wt% LLZNO/Al composite at 320 K and 1 Hz, which was 4.5 times that of pure Al. The simultaneous enhancement on damping capacity, tensile strength and ductility of the LLZNO/Al composite around room temperature can be ascribed to the high damping capacity and the dispersion strengthening of the LLZNO phase, as well as the good bonding between the LLZNO particles and Al matrix resulted from the ARB technique.

In this paper, the microstructure, hardness and defect structure of the oxide dispersion strengthened Fe-16Cr-2W-0.5Ti-0.4Y2O3 (designated as ODS-16Cr) and Fe-16Cr-2W-0.5Ti-0.4Y2O3-4Al-1Zr (ODS-16Cr-Al/Zr) steels irradiated with different doses of He ions were investigated by means of TEM, nanoindentation and positron annihilation spectroscopy. In the both alloys, nano-scale bubbles appeared in the vicinity of the precipitates as well as the grain boundaries. High density dislocation networks were observed as well. Moreover, the hardness of the irradiated steels increased distinctly with increasing He implantation. The irradiation hardening in the ODS-16Cr-Al/Zr alloy is more prominent in comparison with the ODS-16Cr alloy. The positron annihilation results illustrated that concentration of vacancy clusters of ODS-16Cr-Al/Zr steel is higher in the near surface under the larger dose, which is one reason of stronger irradiation hardening below the surface of 300–400 nm. The higher concentration of vacancies or vacancy clusters in ODS-16Cr-Al/Zr samples can be attributed to the fact that the solute Al atoms can effectively trap interstitials, which suppresses the annihilation of interstitials with vacancies.

In this work, we demonstrate the first fully printed WSe 2 resistive random access memory (RRAM) fabricated using aerosol jet printing approach from few layers WSe 2 suspended solution at room temperature on flexible kapton substrate. The printed WSe 2 RRAM exhibits forming free, unipolar behaviour, sub 1-V switching voltage, 2 orders high resistance state (HRS)/low resistance state (LRS) ratio, and large LRS retention time > 2.5 hours. Furthermore, the WSe 2 RRAM exhibits both volatile and non-volatile switching behaviour with a transition set current of 2 µA. In addition, the WSe 2 RRAM retains its functionality even after flexing down to a bending-radii of 5 cm, thus showing suitability for its use as embedded memory in conformal electronics system.

Copper alloys are promising heat sink materials in future fusion reactors owing to the high thermal conductivity and good mechanical properties at medium temperatures. In the present study, aiming at enhancing the strength of copper while keeping the high thermal conductivity, nanoscale W particle dispersion strengthened Cu alloys with different W content of 2 at% (2.6 vol%), 5 at% (6.5 vol%) and 8 at% (10.3 vol%) were fabricated through ball-milling and spark plasma sintering (SPS). The effects of nanoscale W particles on the microstructure, mechanical properties and thermal conductivity of the Cu–W alloys were investigated. The average size of tungsten particles dispersed in copper matrix is 43 nm. The dispersion of W nanoparticles in copper could significantly refine the grain and improve the strength of Cu alloys. The average grain size of Cu-2at%W, Cu-5at%W and Cu-8at%W is as small as 0.84 μm, 0.65 μm and 0.54 μm, respectively. The tensile strength of Cu-8at%W reaches 495 MPa and the elongation is 10.6% at room temperature. The grain size refinement of Cu–W alloys can be attributed to the pinning effects of nanoscale W particles dispersed in the Cu matrix. Although the addition of W nanoparticles leads to a decrease in thermal conductivity, the thermal conductivity for all Cu–W samples is still above 300 Wm-1K-1 at room temperature.

Introducing the transformation-induced plasticity (TRIP) effects into the CoCrNi medium entropy alloy (MEA) to improve the strength and ductile of the alloy is a hot issue in MEA. Herein, we developed two novels non-equiatomic CoCrNi (with Co content of 40 and 50 at. %) MEAs with TRIP effects by increasing the content of Co to lowering the stacking fault energy. It was found that the HCP phase is too tiny to be neglected in Co40 alloy, while in Co50 alloy the 2% HCP phase mainly precipitating at the interface between the annealing twin and the matrix can be found. The tensile test results show that Co40 alloy exhibits a simultaneously improved yield strength (YS) and ultimate tensile strength (UTS) without sacrificing plasticity, while for Co50 alloy, the sample shows significantly increased total elongation (TE) and UTS. The microstructure evolution of Co50 alloy during the deformation process was systematically studied by interrupting the tensile test under different strains. This work proposed that non-equiatomic MEA with more desirable mechanical properties than the equiatomic one can be obtained via introducing TRIP effects.

A clear understanding on the H/He plasma implantation behavior in the plasma facing materials is a key issue to manage the implanted H/He in a future nuclear fusion reactor. In this work, the microstructure evolution of pure tungsten after low-energy (100 eV) and high-fluence (1023~1024 /m2) helium ion implantation was investigated by the synchrotron grazing incidence X-ray diffraction (S-GIXRD) and nanoindentation. Benefiting from the depth dependence of S-GIXRD and nanoindentation, it was found that the unimplanted W surface layer was composed of two zones: the compressed zone with a thickness of ~56 ± 2 nm under the top surface, which was introduced by the mechanical polishing, and the unaffected matrix. The helium implanted W surface layer was composed of four zones along the direction from the top surface to deep depth: the compressed zone with a thickness of ~46 ± 10 nm, transition zone with a thickness of ~146 ± 14 nm, expanded zone, and the matrix. The compressed zone becomes thinner after He implantation possibly owing to the formation of He-complexes. The expanded zone resulted from the helium atoms entering into the tungsten lattice, while the transition zone is a result of competition between the expanding and compressing effects.

Nano-multilayer composites simultaneously exhibit high strength and good radiation resistance because of its huge density of interfaces. However, such outstanding behaviors are influenced by their thermal stability. In this study, we investigated the evolution of microstructure and hardness in Cu/Fe composites fabricated by cross accumulative roll bonding (CARB) with different individual layer thicknesses and annealing time. The results demonstrated that the composites with a layer thickness of 90 nm are more resistant to layer pinch-off and spheroidization, and maintain a relatively high strength after the long-time annealing at 400 °C. By contrast, the decreasing Cu/Fe interface density and severe grain spheroidization in the 30 nm sample lead to a significant drop in hardness. Furthermore, as for helium irradiation response in the 90 nm Cu/Fe composite at 500 °C, some columnar voids with a large aspect ratio appear at Cu/Fe interfaces, demonstrating that void elongation in the normal direction of the interface requires to satisfy both kinetic (along vacancy flux) and thermodynamic (along {111} plane) factors. In addition, the obviously increasing bubble size mainly contributes to the hardening in Cu/Fe multilayers after high-temperature irradiation.

The Li 6.4 La 3 Zr 1.7 M 0.3 O 12 (M = Mo and Cr) and Li 7 − 2 x La 3 Zr 2 − x W x O 12 ( x = 0.1–0.5) solid lithium-ion conductors were prepared by conventional solid state reaction method. The results indicate that partial substitutions by W and Mo ions can stabilize the garnet-like cubic phase of Li–La–Zr–O at room temperature, while the Cr ions substitution cannot even at a content of 15 mol%. The total conductivity of the Li 7 − 2 x La 3 Zr 2 − x W x O 12 lithium conductor is the highest at x = 0.2 (8.7 × 10 − 5 S/cm), and decreases with the increasing W substituting concentration. The Li 6.4 La 3 Zr 1.7 Mo 0.3 O 12 has a higher total conductivity than that of Li 6.4 La 3 Zr 1.7 W 0.3 O 12 . Different from one apparent peak in the Li 7 La 3 Zr 2 O 12 samples, two prominent relaxation-type internal friction peaks related to the short range diffusion of lithium ions were observed in each W or Mo substituted Li 7 La 3 Zr 2 O 12 compounds. The high-temperature IF peaks locate at about 365.9 K and 358.9 K at 1 Hz, corresponding to an activation energy of 0.49 and 0.51 eV for the W and Mo substituted Li 7 La 3 Zr 2 O 12 compounds, respectively. Considering the crystalline structure, it was suggested that the lithium ionic diffusion between 48g(96h)-24d corresponds to the low-temperature peak and 48g(96h)-48g(96h) to the high-temperature peak.

The mechanical properties and thermal conductivity of W-0.5 wt.% TaC alloys prepared by spark plasma sintering as well as ordinary sintering followed by hot rolling and annealing treatment, respectively, were investigated. Tensile tests indicate that below 600 °C there is no tensile plastic deformation while at 700 °C the total elongation of spark plasma sintered (SPSed) W-0.5 wt.% TaC is up to 36%, which is about 3.3 times that of spark plasma sintered W samples. In contrast, the tensile strength and total elongation of rolled W-0.5 wt.% TaC are 717 MPa and 10.7% at 250 °C, respectively. The ductile-brittle transition temperature (DBTT) of rolled W-0.5 wt.% TaC is between 200 °C and 250 °C, about 300 °C lower than that of spark plasma sintered W-0.5 wt.% TaC (~ 600 °C). Annealing decreases the DBTT (~ 200 °C) and improves thermal conductivity from 175 to 186 W/m·K at room temperature. Microstructure analyses indicates that TaC could purify and strengthen grain boundaries by capturing impurity oxygen in tungsten to form Ta2O5. The results indicate that strength, ductility and thermal conductivity can be improved by purifying, hot rolling and subsequent annealing.

A design combining the advantages of oxide dispersion-strengthening, grain-boundary strengthening and hot-swaging leads to a high performance W-0.2%Zr-1%Y2O3 alloy with enhanced strength and ductility. The Y2O3 particles in tungsten could improve the strength and high-temperature properties, while trace Zr (0.2 wt%) could getter oxygen impurity and enhance grain boundary cohesive strength.