Advanced ultra-high strength steels (A-UHSS) are revolutionizing both the steel and automotive industries, therefore it is imperative to study their hot plastic deformation behavior and modeling. The flow characteristics of all hot forming processes consist basically of two competitive phenomena: strain hardening and softening due to dynamic mechanisms (recovery and/or recrystallization). In this research work, the softening parameter was determined in a low carbon A-UHSS microalloyed steel with different amounts of boron (0, 14 and 214 ppm). Experimental stress–strain data of uniaxial hot-compression tests at different temperatures (950, 1000, 1050 and 1100 °C) and strain rates (10–3, 10–2 and 10–1 s–1) were used. The stress–strain relationships as a function of temperature and strain rate were described on the basis of the Estrin, Mecking, and Bergström model. The experimental values of the softening parameter Ω were adjusted using the least-squares method. In general, the results reveal that the softening parameter increases with increasing boron content.

This paper describes the organometallic synthesis of pure rhenium nanoparticles (Re NPs) and their characterization by a combination of state-of-the art techniques (TEM, HAADF-STEM, EDX, WAXS, EA, FT-IR). The Re NPs synthesis is achieved by reducing the [Re2(C3H5)4] complex in solution under a dihydrogen atmosphere and in the presence of hexadecylamine or polyvinylpyrrolidone as stabilizing agents. The so-obtained Re NPs are monodisperse with a mean size of 1.1 nm (0.3) nm and display a spherical shape with a disordered hcp structure.

ReB2 was recently reported to exhibit high hardness and low compressibility, which both are strong functions of its stoichiometry, namely Re to B ratio. Most of the techniques used for ReB2 synthesis reported 1:2.5 Re to B ratio because of the loss of the B during high temperature synthesis. However, as a result of B excess, the amorphous boron, located along the grain boundaries of polycrystalline ReB2, would degrade the ReB2 properties. Therefore, techniques which could allow synthesizing the stoichiometric ReB2 preferably at room temperature are in high demand. Here, we report synthesis of ReB2 powders using mechanochemical route by milling elemental crystalline Re and amorphous B powders in the SPEX 8000 high-energy ball mill for 80 h. The formation of boron and perrhenic acids are also reported after ReB2 powder was exposed to the moist air environment for a 12-month period of time.

Rhenium-oxide-modified supported iridium nanoparticles on silica catalyzes direct hydrogenolysis of glycerol to 1,3-propanediol in an aqueous media. The selectivity to 1,3-propanediol at an initial stage reaches 67%. The yield of 1,3-propanediol reaches 38% at 81% conversion of glycerol. The characterization of catalyst shows that oxidized Re clusters are formed on Ir metal particles. The synergy between Ir metal and ReOx clusters enables the catalytic activity.

The formation process of Rhenium-based diffusion barrier coating on Nickel-based superalloy has been investigated in present paper. The diffusion barrier can be formed by two steps, electroplating and Cr cementation. A tri-layer film structure consisting of Ni / Re~63Ni~37 / Ni was prepared by electrolytic plating onto the substrate of a Ni-based single-crystal superalloy, it was found that the Re-Ni plating film composed of amorphous alloy which is characterized by X-ray diffraction (XRD) analysis. The changes of the barrier films which formed by followed Cr-Pack cementations at 1573 K for 20 min, 50 min, 240 min, 360 min and 600 min, respectively, were investigated by Scan Electron Microscope (SEM) and Electron Probe Micro Analyzer (EPMA). Changing in the thickness of barrier film exhibited two stages, and the composition of barrier film changed along the curve of solubility limit of Ni in Re-Ni-Cr sigma phase.

Investigations on the behavior of the radioactive element technetium frequently use a stable isotope of rhenium as an analogue. This is justified by citing the elements' similar radii, major oxidation states of +7 and +4, and eH-pH diagrams. However, recent studies (e.g.,[1] have shown this analogy to be imperfect. Therefore, one goal of our study is to compare the behavior of these elements with emphasis on the adsorption of perrhenate and pertechnetate (the major forms of Re and Tc in natural waters) on mineral surfaces.

Quantum mechanical calculations were performed on the adsorption of these two anions on relaxed clusters of the well-characterized sulfide galena (PbS) and some other Fe and S-bearing materials. With these calculations, we gain insight into differences between the anions' adsorption behavior, including geometry, adsorption energies, and electronic structure. Differences between interactions on terraces and step edges, the effects of co-adsorbates such as Na+ and Cl-, and chloride complexation are also explored. The influence of water was calculated using homogeneous dielectric fluids.

As a complement to the calculations, batch sorption tests are in progress involving ReO4-/TcO4- solution in contact with Fe metal, 10% Fe-doped hydroxyapatite, goethite, hematite, magnetite, pyrite, galena, and sphalerite.