Search

In this study, high entropy metallic glasses (HEMGs) were developed through a combination of concepts for designing metallic glasses (main element + transition metal + metalloid element) and high-entropy alloys (more than five elements, each element having an atomic concentration between 5 at.% and 35 at.%). The developed metallic glass alloys are composed of Co-Fe-Ni main elements, transition metals (Cr, Mo) and metalloid elements (C, B). Moreover, the present work reports the thermal, mechanical and magnetic properties of (CoFeNi)50(CrMo)50-x(CB)x alloys with x = 20, 25, 30. The developed as-spun HEMGs exhibit typical paramagnetic properties even for a high amount of ferromagnetic elements (Co, Fe, and Ni) and have high elastic modulus (103–160 GPa) and hardness (14–27 GPa), thus possessing mechanical properties similar to well-known Co-based metallic glasses (Co-Cr-Mo-C-B system). In addition, some of the bulk samples prepared with a diameter of 2 mm form bulk metallic glasses with a high compressive strength around 3.5 GPa. The mechanisms determining the stability of the supercooled liquid, as well as the paramagnetic and mechanical properties for the developed non-equiatomic HEMGs, are discussed.

In the field of surface mount technology (SMT), early detection of defects in production machines is crucial to prevent yield reduction. In order to detect defects in the production machine without attaching additional costly sensors, attempts have been made to classify defects in solder paste printers using defective solder paste pattern (DSPP) images automatically obtained through solder paste inspection (SPI). However, since the DSPP images are sparse, have various sizes, and are hardly collected, existing CNN-based classifiers tend to fail to generalize and over-fitted to the train set. Besides, existing studies employing only multi-label classifiers are less helpful since when two or more defects are observed in the DSPP image, the location of each defect can not be specified. To solve these problems, we propose a dual-level defect detection PointNet (D3PointNet), which extracts point cloud features from DSPP images and then performs the defect detection in two semantic levels: a micro-level and a macro-level. In the micro-level, a type of printer defect per point is identified through segmentation. In the macro-level, all types of printer defects appearing in a DSPP image are identified by multi-label classification. Experimental results show that the proposed D3PointNet is robust to the sparsity and size changes of the DSPP image, and its exact match score was 10.2% higher than that of the existing CNN-based state-of-the-art multi-label classification model in the DSPP image dataset.

The low-cost β-titanium alloys, Ti-Cr-Al-Si, have been designed by the addition of a commercial Al-based die-cast alloy (ADC12, Al87.38Cu0.95Si10.65Mg0.27Zn0.30Fe0.32Mn0.11Cr0.02 in at.%) containing Si content. The microstructural investigation on Ti84-xCr16(ADC12)x (x = 6, 16 at.%) alloys exhibited that the addition of 6 at.%ADC12 completely dissolved in the β-Ti phase, and exhibited reasonable yield strength by solid solution hardening of the β-Ti phase with large plasticity. The addition of 16 at.%ADC12 effectively reduces the cost of the β-titanium alloys and induces microstructural evolution with formation of Ti-silicide. The β-Ti phase containing high content of solutes and the very fine Ti5Si3 phase that segregated in the interdendritic regions, due to Si solute partitioning during dendritic solidification, mediates outstanding tensile mechanical properties (1015 MPa in yield strength and 17.5% in elongation). These results reveal that the alloy designs using the commercial materials containing various solute elements can facilitate the development of the competitive low-cost β-titanium alloys with excellent mechanical properties.

Ti45Cu40Ni7Zr5Sn2.5Si0.5 alloys were prepared under various cooling rate conditions during solidification. The alloys exhibited different volume fractions of B2 particles with 0 ~ 40 vol% in an amorphous matrix. Monolithic bulk metallic glass of 1 mm diameter showed no macroscopic plasticity and exhibited the typical vein patterns in a maximum shear stress plane on the fracture surface. However, a bulk metallic glass composite containing the B2 particles revealed obvious plasticity (~ 5.6%) with a remarkable work-hardening behavior that resulted from a stress-induced martensitic transformation of the B2 particles. Moreover, the composite displayed the complicated fracture morphologies containing of three types of fracture features. Through detailed investigations on the microstructural evolution, mechanical, deformation and fracture characteristics, the influence of B2 particle on overall behavior of the TiCu-based bulk metallic glass composites was elucidated. Keywords: Bulk metallic glass Composite, Mechanical properties, Martensitic transformation, Fracture behavior

In this work, we investigated the effect of boron addition on glass-forming ability and mechanical properties of Co-Cr-Mo-C alloys. The starting alloy was (Co0.65Cr0.13Mo0.22)80C20 derived from the Co65Cr13Mo22 ternary eutectic composition. This alloy is almost fully crystalline and exhibits brittle mechanical properties. Replacing carbon with boron allows obtaining bulk metallic glasses (BMGs) and bulk metallic glass composites. The designed alloys show very high strength (∼4100 MPa), wide super-cooled liquid region (∼100 K) and large endothermic enthalpy of the supercooled liquid region (∼35 J/g), indicating high thermal stability. The electronegativity difference and supercooled liquid region of the present alloys are comparable to rare-earth elements containing BMGs. The physical properties of the present alloys corresponded well with the alloy design strategy based on the unified parameter using the glass transition temperature, fracture strength, and molar volume. Furthermore, we propose the optimum compositional condition for glass formation by controlling the carbon-to-boron ratio and the influence of carbon on phase formation in this alloy system is discussed.

Bulk metallic glass composites containing micro-scale B2 particles are subject to investigation with regards to the influence of B2 particles and interfacial stress and strain distribution on the viscous flow behavior at a super-cooled liquid state. An increased volume fraction of B2 particles leads to an increase of minimum viscosity and influences viscous flow behavior before crystallization. In high temperature deformation, the bulk metallic glass shows homogeneous deformation feature. However, the heterogeneous deformation feature is found in thermoplastically deformed bulk metallic glass composite. The strong stain accumulation and sluggish viscous flow occur around B2 particles, which are caused by the heterogeneous stress distribution linked to stress concentration and shear stress impediment around B2 particles. The sluggish viscous flow of super-cooled liquids around B2 particles during high temperature deformation induces an increase of viscosity and strongly affects the viscous flow behavior of Ti-based bulk metallic glass composites containing micro-scale spherical B2 particles.

The as-cast Mg-9Li alloys with difference Al-Si addition were fabricated using induction casting method under the argon atmosphere and then warm rolling process was performed at 473 K. The Al-Si addition to Mg-9Li alloy leads to the formation of Mg2Si intermetallic compounds and microstructural evolutions such as increased volume fraction of α-Mg phases and changed morphology of α-Mg primary phase on the as-cast specimens. Moreover, the addition of 0.05 wt.% Ti elements on Mg-9Li-3(Al-Si) alloy raised the further microstructural evolutions, e.g. volume fraction of α-Mg phases, which bring about change in the microstructure after warm rolling process. The effects of this micro alloying influences the formation of fine microstructure after warm rolling process, which is the main factor in determining the mechanical properties. With these microstructural evolutions, tensile strength was increased from 101.71 MPa to 247.41 MPa by the minor alloying and warm rolling process. Moreover, the remarkably enhanced strength of Mg-9Li-3(Al-Si) alloy was the results of the addition of 0.05 wt.% Ti from 247 MPa to 412 MPa. Furthermore, the warm press-forming tests were carried out at 523 K to evaluate the applicability of this novel alloy for commercial products.

Crystallization and phase transformation behaviors of Ti 45 Cu 40 Ni 7.5 Zr 4 Sn 2.5 Si 1 bulk metallic glass composite with B2 particles were investigated by isothermal heat treatment with systematic TEM analysis. The crystallization of the amorphous phase occurs in two steps with the formation of nanocrystalline followed by the precipitation of γ-TiCu phase. On the one hand, the metastable B2 phase still maintained until crystallization process is completed. However, when the sample was heat treated longer times, the cubic B2 phase are transformed into the tetragonal γ-TiCu phase with highly lattice distortion.

The separation of high purity Si for solar cells from Al-Si alloy melt in the mushy zone was investigated using an advanced centrifugal technique. The efficiency of separating Si, based on the weight ratio of separated Si to Si in alloy melt, was maximized by optimizing the permeability of a porous structure of Si (Si foam.) For the optimization of the permeability, two fundamental microstructure variables, size and the solid fraction of primary Si platelets, were controlled by adjusting the Si content in the melts and the rotation start temperature, respectively. The best separation efficiency (48.3% with 3N purity) was achieved when Si content in melt was 24% and the solid fraction was 8.7%. The melt with 23% Si led to a higher separation efficiency (69.8%) for a solid fraction of 10.4%, but Al sandwiched between the Si platelets resulted in a decrease in the purity to 2N.

In this study, A series of the high strength (T82Sn18)100-xNbx (x=0, 1, 3, 5, and 9 at%) ultrafine eutectic alloys with large plasticity are developed by suction casting method. The Ti82Sn18 binary eutectic alloy consists of a mixture of a hcp Ti3Sn and a α-Ti phases having the plate-like lamellar type duplex structure with micro scaled eutectic colony. From the (T82Sn18)97Nb3, the alloy display structural heterogeneous distribution of ultrafine-scaled phases composed of β-Ti(Nb) solid solution surrounded by alternating plate-like shaped Ti3Sn and α-Ti phases. With increasing Nb content, the volume fraction of β-Ti is continuously increased, which induced improving mechanical properties both strength and plasticity. Especially, (Ti82Sn18)91Nb9 alloy has the outstanding combination of the high strength (σ y ≈1.1 GPa) and large plasticity (e p ≈36%) at room temperature.

Quaternary Ni-Ti-Hf-Zr high temperature shape memory alloys containing different Zr content (0–15 at.%) were prepared by arc melting and suction casting. The addition of Zr led to change in lattice parameters and monoclinic angle of B19′ martensite phase. The phase transformation temperature as well as yield strength of the alloys gradually increased with increasing the Zr content. Moreover, the alloys exhibited significant changes in phase transition and deformation behaviors. With the addition of Zr up to 7 at.%, the alloys exhibited double yielding and two-step phase transition behaviors. In contrast, alloys containing 10 and 15 at.%Zr revealed single yielding and one-step phase transition behaviors. These distinctions on phase transition and yielding behaviors of the alloys were mainly related to the structural evolution related to twinning mode in martensite phase of as-cast alloys originated from the change of lattice distortion during martensitic transformation by increasing of Zr content. Through detailed investigations on the microstructural features, thermal characteristics, mechanical properties and structural evolution on deformation of the alloys, the influence of Zr content on phase formation, phase transition and deformation behavior of Ni-Ti-Hf-Zr high temperature shape memory alloys was elucidated.

Effects of Ca addition on the microstructure and mechanical properties of as-extruded Mg-11Li-3Al-1Sn-0.4Mn-xCa alloys with x = 0 and 0.8 were investigated. The Ca addition on the Mg-11Li-3Al-1Sn-0.4Mn alloy can lead to no change in the constituent phases, which consist of β -Li, α -Mg, MgLi 2 Al and MgLi 2 Sn. However, the microstructure obtained after the extrusion process clearly exhibits different morphologies, of which Ca free alloy shows homogeneously distributed intermetallic compounds and Ca containing alloy display well-arranged intermetallic compounds along the extrusion direction. From these microstructural evolutions, even though the tensile strength decreased, the tensile elongation was significantly improved from 35.1 to 88.6%. The effect of Ca addition on the microstructural evolution and increased plastic deformability have been discussed using grain refinement, grain boundary sliding and micro crack propagation.

Intelligent agents gather information and perceive semantics within the environments before taking on given tasks. The agents store the collected information in the form of environment models that compactly represent the surrounding environments. The agents, however, can only conduct limited tasks without an efficient and effective environment model. Thus, such an environment model takes a crucial role for the autonomy systems of intelligent agents. We claim the following characteristics for a versatile environment model: accuracy, applicability, usability, and scalability. Although a number of researchers have attempted to develop such models that represent environments precisely to a certain degree, they lack broad applicability, intuitive usability, and satisfactory scalability. To tackle these limitations, we propose 3-D scene graph as an environment model and the 3-D scene graph construction framework. The concise and widely used graph structure readily guarantees usability as well as scalability for 3-D scene graph. We demonstrate the accuracy and applicability of the 3-D scene graph by exhibiting the deployment of the 3-D scene graph in practical applications. Moreover, we verify the performance of the proposed 3-D scene graph and the framework by conducting a series of comprehensive experiments under various conditions., Early Access

Intelligent robots such as social robots and home service robots that are being developed nowadays are required to have the ability to naturally communicate with users in natural language. Beyond simple data retrieval and simple dialogue level, we propose a new Human-Robot Interaction (HRI) system that enables a robot to understand and reason the environment around a user and present information about them in natural language, whenever the user asks a question to the robot. For its intelligent HRI, based on Dynamic Memory Networks (DMN), a neural network for Visual Question Answering (VQA), we propose a new full sentence VQA network model called Full-Sentence Highway Memory Network (FSHMN). For its robot platform, a three DOF robotic head was used which has a neck with three motors and a tablet PC head. To verify the feasibility of the proposed system, an experiment is performed in which a user and a robot interact with each other in a way of question answering in a customized kitchen environment. Through the experiment, we not only demonstrated the effectiveness of applying deep learning to HRI applications in real environments but also presented a new insight into HRI.

The gradient Al2O3 layer coated bimodal structured composite substrate was fabricated using combined chemical and hydrothermal processes. Selective etching was performed to remove micrometer-sized α-Al dendrites from the ultrafine structured matrix. Simultaneously, a hydrothermal oxidation process was used to grow Al2O3 on the surface of the porous structured substrate. In particular, the architecture of coated metal oxide (Al2O3) can be altered from a rectangular to a pyramidal shape depending on the hydrothermal process time. Keywords: Ultrafine eutectic composite, Porous materials, Dealloying, Hydrothermal process

The microstructure and compressive mechanical properties of squeeze casted Mg 15Li xAl (x = 0, 1, 3 and 5 wt%) alloys have been investigated. With addition of Aluminum (Al) in Mg 15Li alloy, the compressive yield strength is continuously increased and density is slightly decreased. This improved mechanical property is mainly attributed to the precipitation of Al Li intermetallic compounds into the β-phase and grain size refinement of β-phase. Accordingly, lightweight and high specific strength Mg Li Al alloys were developed successfully via proper addition of Al contents, resulted from favorable microstructural evolution.

In this study, we investigate the progress of stress-induced martensitic transformation depending on the stress state on TiCu-based bulk metallic glass composite via systematical transmission electron microscopy analysis. On the stage of elastic deformation (before yielding), the martensitic transformation from austenite B2 phase to martensite B19′ phase occurred from interface between B2 particle and amorphous matrix with ∼50 nm region. Just after yielding, the martensitic transformed region was extended toward B2 particle with distance of ∼130 nm from the interface. Moreover, the deformation twinning of martensite B19′ phase in martensitic transformed region was also observed. When 1% plastic deformation occurred, the martensitic transformed region reached up to ∼600 nm. Based on these results, it is believed that the high level of stress can be concentrated around the interface due to the elastic mismatch of B2 and amorphous phases. As a result, structural gradient morphology originated from phase transition was formed into the B2 particle during early stage of deformation.

In this study, alloys with composition of equi-atomic substituted TiZrHfNiCu, TiZrHfNiCuCo, and TiZrHfNiCuNb high-entropy alloys (HEAs) were produced by suction casting method. The effects of addition elements on phase composition, microstructure and mechanical behaviors of the HEA were studied. The suction casted Ti20Zr20Hf20Ni20Cu20 HEA exhibits single C14 Laves phase (MgZn2-type) with fine homogeneous microstructure. When Co or Nb elements are added, morphologies are slightly modulated toward well-developed dendritic microstructure, phase constitutions are significantly changed from single Laves phase to mixed multi-phases as well as mechanical properties are also altered with increased plasticity and high strength. It is believed that modulated mechanical properties are mainly ascribed to the change of phase constitution and crystalline structure, together with the microstructural characteristics. This clearly reveals that the selection and addition of supplementary elements based on the formation rule for HEAs play an important role on the evolution of phase, microstructural morphology and mechanical properties of Ti20Zr20Hf20Ni20Cu20 HEA.

Systematic investigations for the influence of the microstructural change derived from compositional tuning in Al-rich corner of Al–Cu–Si system on mechanical properties demonstrate that mechanical characteristic of ultrafine eutectic composites strongly depend on the crystallinity, length scale and volume fraction of constituent phases. Ultrafine eutectic composites can be divided into two categories: 1) whether primary phases exist or not and 2) the types of matrix phases, i.e., single eutectic or bimodal eutectic. The features of primary phases play a principal role on the macroscopic property. Ductile α-Al phase is very effective to improve the plasticity while brittle Al2Cu intermetallic phase deteriorates obviously mechanical performance. In addition, bimodal eutectic matrix alloys composed of eutectics with different length scale and morphology show superior mechanical properties than single eutectic matrix alloys. Based on the microstructural studies, it is believed that high strength is originated from ultrafine scale microstructure and enhanced plasticity is supported by strain gradient plasticity. These results reveal that mechanical properties of the ultrafine eutectic composites can be properly optimized via control of chemical and topological governing factors. Keywords: Ultrafine eutectic composite, Microstructure, Heterogeneity, Deformation mechanism

To perform a home service task through cooperation with a human in a real environment, a robot needs to deal with the environmental changes and accordingly plan appropriate behavior sequence. For this purpose, in this paper, we propose an adaptive task planner which is based on memory and reasoning. A robot perceives user behaviors and objects using an RGB-depth and thermal sensor. The robot stores a temporal sequence of behaviors for performing a task in its episodic memory that is realized by a sequence to sequence network. When the user command is given, the episodic memory is used to retrieve the behavior sequence to carry out the command. On the other hand, when the robot perceives user behaviors, the robot postpones its behavior till his/her behavior is stopped. Once stopped, the episodic memory retrieves the behavior sequence to conduct a task that the user has intended. A task scheduler schedules the behavior sequence from the memory and sends it to an internal simulator. The internal simulator confirms the behavior sequence to be executable and then if executable, it sends the next executable behavior to the execution module. If a behavior fails in the internal simulation test, fast forward planner generates an alternative behavior sequence to resolve the failed behavior problem. The effectiveness and applicability of the proposed planner is demonstrated by a wheel-based humanoid robot.

The microstructural evolution and crack filling phenomena of (Al81Cu13Si6)100−x(Sn57Bi43) x (x = 0, 1, and 3 at.%) composites was investigated. The Sn and Bi elements were selected by considering the ability for liquid phase separation when combined with Al, Cu, and Si. Because of liquid phase separation, both Al-Cu-Si-rich L1 and Sn-Bi-rich L2 phases separately solidified at different temperatures yielding a trimodal eutectic structure in the cast alloys. The Sn and Bi elements have high mobilities due to the large interface of the eutectic microstructure and tend to strongly diffuse towards higher strained region during heat treatment. Furthermore, the mobile Sn and Bi elements in the Al-Cu-Si-based bimodal eutectic structure evidently fill cracks during warm rolling at 423 K. These results reveal that the developed alloy system has simultaneously dual self-healing characteristics, derived from the both precipitated Sn-Bi-rich particles and low melting agent, and the proposed alloy design based on liquid phase separation provides a novel strategy for creating self-crack filling metallic materials.

In the present study, the microstructural evolution and improving the mechanical properties have been achieved in Fe–Nb binary eutectic alloy via controlling the amount of boron (B) content. The addition of B leads to evolution of a unique microstructure with different length-scale heterogeneities, i.e., formation of bimodal structure, spherical colonies containing length-scale heterogeneity and precipitation of primary NbFeB phase. Following the evolution of microstructure, the mechanical properties including yield strength and plastic strain were significantly enhanced from 1100 MPa to 1660 MPa and from ∼4% to ∼20%, respectively. To elucidate deformation mechanism fracture topography and lateral surface morphology analyses are performed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). From these observations two distinct plastic deformation mechanisms can be suggested by following ways: (1) deformation-induced rotation motion of dendrites/eutectic colonies and (2) deformation-induced interface migration of lamellar structure.

In this work, the role of individual B2 particles with bimodal length scale on work-hardening and plastic deformation behaviors of Ti-based bulk metallic glass composites has been studied by systemic microstructural and mechanical investigations. At the early stage of plastic deformation, work-hardening characteristic was clearly observed. This work-hardening behavior can be supported by the martensitic transformation and the deformation induced twinning in both small- and large-sized B2 particles during deformation. On progress of plastic deformation after work-hardening, small-sized B2 particles (1–10 μm) were penetrated by propagation of main shear bands while large-sized B2 particles (100–200 μm) were severely interacted with shear bands leading to formation of multiple shear bands and impeding the propagation of principal shear bands. This reveals that each B2 particle with different length scale plays a distinct role on the stage of plastic deformation depending on the particle size.

In present work, work-hardening behavior of TiCu-based bulk metallic glass composite with B2 particles has been studied by systemic structural and mechanical investigations. After yield, pronounced work-hardening of the alloy was clearly exhibited, which was mainly related to the martensitic transformation as well as the deformation twinning in B2 particles during deformation. At the early plastic deformation stage (work-hardening stage), the stress-induced martensitic transformation from B2 phase to B19` phase and deformation-induced twinning of B19` phase was preferentially occurred in the around interface areas between B2 phase and amorphous matrix by stress concentration. The higher hardness value was observed in vicinity of interface within the B2 particles which are probably connected with martensitic transformation and deformation twinning. This reveals that the work-hardening phenomenon of this bulk metallic glass composite is a result of the hardening of B2 particles embedded in amorphous matrix.

Formation of an icosahedral phase in the bulk glass forming alloy during crystallization from amorphous phase and solidification from melt is investigated. The icosahedral phase with a size of 10 to 15 nm forms as a thermodynamically stable phase at intermediate temperature during the transformation from amorphous to crystalline phases such as Laves and -(Ti-Zr) phases, indicating that the existence of the icosahedral cluster in the undercooled liquid. On the other hand, the icosahedral phase forms as a primary solidification phase even though the Laves phase is stable at high temperature, which is can be explained based on the high nucleation rate of icosahedral phase relative to that of competing crystalline Laves phase due to lower interfacial energy between icosahedral and liquid phases.

Porous metallic glass compact (PMGC) using electro-discharge sintering (EDS) process of gas atomized Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 metallic glass powder was developed. The formation of uniform PMGC can only be achieved when low electrical input energy was applied. Functional iron-oxides were formed on the surface of PMGCs by hydrothermal technique. This finding suggests that PMGC can be applied in the new area such as catalyst via hydrothermal technique and offer a promising guideline for using the metallic glasses as a potential functional application.

In this study, electrically conductive Al-based metallic glass (MG) has been applied as an alternative of oxide glass in silver paste. Al85Ni5Y8Co2 MG powder was produced by gas atomization process and simultaneously classified depending on the size of powder. The wetting behavior of MG was dramatically altered by the degree of crystallinity and the size of MG powder, resulting in the different sinterability of silver (Ag) and contact area between Si emitter and Ag. The Ag electrode with smaller MG powder shows much denser structure of Ag and larger contact area, leading to low contact resistance, 0.69 ± 0.38 at p-type and 0.56 ± 0.13 mΩcm2 at n-type emitter.

The influence of cold rolling on the tensile mechanical properties and deformation behavior of Ti-based bulk metallic glass (BMG: Ti40Zr25Ni8Cu9Be18) and β-Ti dendrite reinforced bulk metallic glass matrix composite (BMGMC: Ti40.2Zr18Ni2.85Cu7.65Be12.3Nb19) has been investigated. The cold-rolled BMG and BMGMC samples with 20% thickness reduction ratio exhibit a pronounced tensile plasticity of 0.8% and 4%, respectively. The malleable behavior of the cold-rolled samples originates from the internal structural evolution and modulation of elastic properties.

Chemical heterogeneity in Ti–Fe ultrafine eutectic structure has been introduced by addition of Bi without structural heterogeneities such as length-scale, volume fraction and morphology of lamellar and colony structures. The detailed microstructural investigation clearly reveals that the Bi was highly saturated at the colony boundary of the ultrafine eutectic alloys. The chemical heterogeneity introduced by the additional Bi in the present investigation effectively dissipates the localization of the stress thus improving the plasticity up to 8.5% without compromising the strength of 2100 MPa.

Tensile mechanical properties and deformation behavior of as-cast and cold-rolled β-Ti dendrite reinforced Ti-based bulk metallic glass matrix composite (BMGMC: Ti40.2Zr18Ni2.85Cu7.65Be12.3Nb19) have been investigated. The tensile test of the pre-strained BMGMC via cold rolling manifests a distinct necking and large plasticity of ∼4%. Such an improvement in tensile mechanical properties of the cold-rolled BMGMC is attributed to the strain-induced change of elastic properties of the glassy matrix, resulting in malleable interaction between the reinforced dendrites and the microstructural evolution derived from pre-introduced multiple shear bands, leading to uniform distribution of shear strain.

The accumulation of viral RNA depends on many host cellular factors. The hexagonal peroxisome (Hex1) protein is a fungal protein that is highly expressed when the DK21 strain of Fusarium graminearum virus 1 (FgV1) infects its host, and Hex1 affects the accumulation of FgV1 RNA. The Hex1 protein is the major constituent of the Woronin body (WB), which is a peroxisome-derived electron-dense core organelle that seals the septal pore in response to hyphal wounding. To clarify the role of Hex1 and the WB in the relationship between FgV1 and Fusarium graminearum , we generated targeted gene deletion and overexpression mutants. Although neither HEX1 gene deletion nor overexpression substantially affected vegetative growth, both changes reduced the production of asexual spores and reduced virulence on wheat spikelets in the absence of FgV1 infection. However, the vegetative growth of deletion and overexpression mutants was increased and decreased, respectively, upon FgV1 infection compared to that of an FgV1-infected wild-type isolate. Viral RNA accumulation was significantly decreased in deletion mutants but was significantly increased in overexpression mutants compared to the viral RNA accumulation in the virus-infected wild-type control. Overall, these data indicate that the HEX1 gene plays a direct role in the asexual reproduction and virulence of F. graminearum and facilitates viral RNA accumulation in the FgV1-infected host fungus.

We report on the formation of Ti-Cu-Ni-Zr-Sn-Si bulk metallic glass composites containing bimodal size of B2 TiCu compounds. The small B2 TiCu compound with a size of 1 to 10 μm has a strong influence on the oscillation of the shear stress, thus causing wavy propagation of the shear bands. In contrast, the large B2 TiCu compound with a size of 70 to 150 μm dissipates the shear stress by branching and multiplication of the shear bands. By forming the bimodal size of B2 TiCu compound, it is possible to determine the harmonic influence to further enhance the plasticity of the Ti-Cu-Ni-Zr-Sn-Si bulk metallic glass composites.

In the present study, we propose that the glass stability of an amorphous oxide film is highly dependent on the interface stability between the amorphous oxide and the amorphous substrate. The interface stability is closely linked to the thermal stability of the amorphous substrate, which is changed by the chemical composition shift during formation of the oxide layer. Therefore, significant improvement of the oxidation resistance in metallic glass systems can be achieved by controlling the compositional changes underneath the oxide layer.

In the present study, we propose that the formation of amorphous oxide layers with an enhanced thermal stability can significantly improve the oxidation resistance of metallic glass in the supercooled liquid (SCL) state. Addition of a small amount of Be (2 at.%) in Cu46Zr46Al8 widens the SCL region and simultaneously improves the oxidation resistance of the SCL. For Cu46Zr46Al8, the initial amorphous oxide completely transforms into the crystalline oxide far below the glass transition temperature during continuous heating, while for Cu45Zr45Al8Be2, the amorphous oxide remains after heating up to the SCL region, thus significantly improving the oxidation resistance of the SCL.