High-Temperature Strength of Titanium Alloys Alloyed with Silicon,Aluminum, and Zirconium in Air

We study the behavior of VT1-0 titanium alloy alloyed with silicon, aluminum, and zirconium in the process of oxidation in air at 800°C for 30 h. It is shown that, as a result of alloying of the alloy with silicon up to 6 wt.%, its high-temperature strength becomes more than two times higher. This effect is connected with the influence of silicon on the diffusion processes in the metal and scale and changes in the morphology of scale. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 41, No. 2, pp. 83–88, March–April, 2005.     

Electromagnetic Witness Transducers of Pre-Fracture of Structures

Russian Journal of Nondestructive Testing - Appropriate sensors and measuring systems are required to gather information on the fatigue state of technical devices and predict their residual life...     

Formation of Silicides and their Influence on the Structure and Properties of Cast Alloys of the Ti–18Nb–xSi System for Biomedical Purposes

Materials Science - We study new biomedical alloys of the Ti–18Nb– x Si system with 0.6–1.2 wt.% Si both in the as-cast state and quenched in water after holding at temperatures...     

An artificial biomineral formed by incorporation of copolymer micelles in calcite crystals

Biominerals exhibit morphologies, hierarchical ordering and properties that invariably surpass those of their synthetic counterparts. A key feature of these materials, which sets them apart from synthetic crystals, is their nanocomposite structure, which derives from intimate association of organic molecules with the mineral host. We here demonstrate the production of artificial biominerals where single crystals of calcite occlude a remarkable 13 wt% of 20 nm anionic diblock copolymer micelles, which act as 'pseudo-proteins'. The synthetic crystals exhibit analogous texture and defect structures to biogenic calcite crystals and are harder than pure calcite. Further, the micelles are specifically adsorbed on {104} faces and undergo a change in shape on incorporation within the crystal lattice. This system provides a unique model for understanding biomineral formation, giving insight into both the mechanism of occlusion of biomacromolecules within single crystals, and the relationship between the macroscopic mechanical properties of a crystal and its microscopic structure.     

Electrodeposition of polypyrrole–titanate nanotube composites coatings and their corrosion resistance

Polypyrrole (PPy) films (2 μm) containing titanate nanotubes (TiNT) were deposited from 0.5 mol dm⁻³ pyrrole (Py) and 1 g dm⁻³ of TiNT in 0.1 mol dm⁻³ aqueous oxalic acid on 904 L stainless steel (SS) 0.1 mm thickness at 298 K. Electron microscopy showed that the nanotubes were adsorbed on the PPy surface and uniformly dispersed in the polymer matrix. The PPy/TiNT composite contained <10 wt.% titanates which showed an increase of 53% hardness compared with polypyrrole alone. The TiNT provide nucleation centres to catalyze the polymerization of pyrrole and can adsorb up to 240 mg g⁻¹ of the monomer. The corrosion rates for SS, SS/PPy and SS/PPy/TiTN composites, evaluated by linear sweep voltammetry and open-circuit potential measurements in 3% w/v NaCl, were 1.61, 0.008 and 0.004 mg dm⁻² day⁻¹, respectively, indicating that corrosion rates of stainless steel decreased by up to three orders of magnitude in the presence of the composite films.