Electro-explosive alloying of VT6 alloy surface by boron carbide powder with the subsequent electron-beam treatment

The formation of electro-explosive alloying zone with the thickness up to 50 µm has been revealed. It has been shown that it has a gradient structure, characterized by the decrease of carbon and boron concentration with the increase of the distance up to the treatment surface. The subsequent electron-beam treatment of alloying zone leads to flattening of alloying surface relief and is accompanied by the formation of a multilevel structure at the depth up to 30 µm, characterized by the interchange of some layers with a different level of alloying, having structure of a submicro- and nanoscale level

Interfacial microstructure and shear strength of Ti-6Al-4V/TiAl laminate composite sheet fabricated by hot packed rolling

A two layer Ti-6Al-4V(wt%)/Ti-43Al-9V-Y(at%) laminate composite sheet with a uniform interfacial microstructure and no discernible defects at the interfaces has been prepared by hot-pack rolling, and its interfacial microstructure and shear strength were characterized. Characterization of the interfacial microstructure shows that there was an interfacial region of uniform thickness of about 250 μm which consisted of two layers: Layer I on the TiAl side which was 80 μm thick and Layer II on the Ti-6Al-4V side which was 170 μm thick. The microstructure of Layer I consisted of massive γ phases, needlelike γ phases and B2 phase matrix, while the microstructure of Layer II consisted of α₂ phase. The microstructure of the interfacial region is the result of the interdiffusion of Ti element from Ti-6Al-4V alloy layer into the TiAl alloy layer and Al element from the TiAl alloy layer into the Ti-6Al-4V alloy layer. The shear strength measurement demonstrated that the bonding strength between the TiAl alloy and Ti-6Al-4V alloy layers in the laminate composite sheet was very high. This means that the quality of the interfacial bonding between the two layers achieved by the multi-path rolling is high, and the interface between the layers is very effective in transferring loading, causing significantly improved toughness and plasticity of the TiAl/Ti-6Al-4V laminate composite sheet

Tabulation of Asbestos Related-Terminology

The definition of asbestos often varies depending on the source or publication in which it is used. This report summarizes asbestos-related definitions taken from a variety of academic, industrial, and regulatory sources. This summary is by no means complete but includes the majority of significant definitions currently applied in the discipline. Educational levels: Graduate or professional, Undergraduate upper division

Zero field magnetic phase transitions and anomalous low temperature upturn in resistivity of single crystalline α-TmAlB4

In this study, pure α-TmAlB4 (YCrB4structure)single crystals were grown with no β-TmAlB4 (ThMoB4structure) intergrowth, and zero magnetic fieldtransitions were confirmed through specific heat capacity, magnetization, and electric resistivity measurements. The anomalous magnetic transition was found at approximately 6.2 K with long range antiferromagnetictransition at 5.6 K. The difference in field dependence between these two transitions indicates that they do not share a common magnetic origin. In addition, we investigated electrical resistivity down to 20 mK, and found upturn behavior at around 0.8 K. The low temperature upturn anomaly in resistivity was not found for other compounds of investigation for RAlB4 (R=rare earth elements), which suggests that an α-RAlB4system has a significantly different ground state, compared to a β-RAlB4 system

Magnetic anisotropy and geometrical frustration in the Ising spin-chain system Sr5Rh4O12

A structural and thermodynamic study of the newly synthesized single crystal Sr5Rh4O12 is reported. Sr5Rh4O12 consists of a triangular lattice of spin chains running along the c-axis. It is antiferromagnetically ordered below 23 K with the intrachain and interchain coupling being ferromagnetic (FM) and antiferromagnetic (AFM), respectively. There is strong evidence for an Ising character in the interaction and geometrical frustration that causes incomplete long-range AFM order. The isothermal magnetization exhibits two step-like transitions leading to a ferrimagnetic state at 2.4 T and a FM state at 4.8 T, respectively. Sr5Rh4O12 is a unique frustrated spin-chain system ever found in 4d and 5d based materials without a presence of an incomplete 3d-electron shell.Comment: 15 pages, 4 figure

Time-resolved imaging of the laser forward transfer of liquids

Time-resolved imaging is carried out to study the dynamics of the laser-induced forward transfer of an aqueous solution at different laser fluences. The transfer mechanisms are elucidated, and directly correlated with the material deposited at the analyzed irradiation conditions. It is found that there exists a fluence range in which regular and well-defined droplets are deposited. In this case, laser pulse energy absorption results in the formation of a plasma, which expansion originates a cavitation bubble in the liquid. After the further expansion and collapse of the bubble, a long and uniform jet is developed, which advances at a constant velocity until it reaches the receptor substrate. On the other hand, for lower fluences no material is deposited. In this case, although a jet can be also generated, it recoils before reaching the substrate. For higher fluences, splashing is observed on the receptor substrate due to the bursting of the cavitation bubble. Finally, a discussion of the possible mechanisms which lead to such singular dynamics is also provided

On the theory of dendritic growth: Soret and temperature-dependent diffusion effects

An analytical solution is found for the problem of the growth of an isolated dendrite in a convective binary melt with allowance for the Soret and temperature-dependent diffusion effects. Nonlinear impurity transport is shown to radically change the impurity concentration in front of the growing crystal and, correspondingly, the concentration supercooling, which is responsible for the condition of choosing the dendrite tip growth rate. © 2013 Pleiades Publishing, Ltd

Construction and Operation of a Laboaratory Size Thum Cell

Electrolytic silver refining was not perfected until the end of the nineteenth century. During the process of development, two systems of silver refining have come into prominence: the Moebius and the Thum types

Foliar lead uptake by lettuce exposed to atmospheric fallouts

Metal uptake by plants occurs by soil−root transfer but also by direct transfer of contaminants from the atmosphere to the shoots. This second pathway may be particularly important in kitchen gardens near industrial plants. The mechanisms of foliar uptake of lead by lettuce (Lactuca sativa) exposed to the atmospheric fallouts of a lead-recycling plant were studied. After 43 days of exposure, the thoroughly washed leaves contained 335 ± 50 mg Pb kg−1 (dry weight). Micro-X-ray fluorescence mappings evidenced Pb-rich spots of a few hundreds of micrometers in diameter located in necrotic zones. These spots were more abundant at the base of the central nervure. Environmental scanning electron microscopy coupled with energy dispersive X-ray microanalysis showed that smaller particles (a few micrometers in diameter) were also present in other regions of the leaves, often located beneath the leaf surface. In addition, submicrometric particles were observed inside stomatal openings. Raman microspectrometry analyses of the leaves identified smelter-originated Pb minerals but also secondary phases likely resulting from the weathering of original particles. On the basis of these observations, several pathways for foliar lead uptake are discussed. A better understanding of these mechanisms may be of interest for risk assessment of population exposure to atmospheric metal contamination