Nanocrystalline Ti Produced by Cryomilling and Consolidation by Severe Plastic Deformation

We report on a study of the nanocrystalline structure in Ti, which was produced by cryogenic milling followed by subsequent consolidation via severe plastic deformation using high pressure torsion. The mechanisms that are believed to be responsible for the formation of grains smaller than 40 nm are discussed and the influence of structural characteristics, such as nanometric grains and oxide nanoparticles, on Ti hardening is established

Nanostructural Engineering of Steel

The concept of microstructural engineering of steels is well established and is the basis for a wide range of processes and products. Recently, though, there has been increasing emphasis in developing microstructures that have submicron length scales and also in understanding in far greater detail the structures and solute effects that are occurring at the nanoscale. In this review it is proposed that we are heading towards the situation where we are applying nanostructural engineering concepts in the development of new steels. A range of examples are given as well as a discussion of the potential impact of new processing routes. Clearly the future advances will be driven through improved characterization methods, such as atom probe tomography, in combination with advanced modeling

A study of the strengthening mechanism in the thermomechanically processed TRIP/TWIP steel

The strengthening mechanism responsible for the unique combination of ultimate tensile strength and elongation in a multiphase Fe-0.2C-1.5Mn-1.2Si-0.3Mo-0.6Al-0.02Nb (wt%) steel was studied. The microstructures with different volume fraction of polygonal fenite, bainite and retained austenite were simulated by controlled thermomechanical processing. The interupted tensile test was used to study the bainitic ferrite, retained austenite and polygonal ferrite behavior as a function of plastic strain. X-ray analysis was used to characterize the volume fraction and carbon content of retained austenite. TEM and heat-tinting were utilized to analyze the effect of bainitic fenite morphology on the strain induced transformation of retained austenite and retained austenite twinning as a function of strain in the bulk material. The study has shown that the austenite twinning mechanism is more preferable than the transformation induced plasticity mechanism during the early stages of deformation for a microstructure containing I5% polygonal ferrite, while the transformation induced plasticity effect is the main mechanism in when there is 50% of polygonal ferrite in the microstructure. The baillitic fenite morphology affects the deformation mode of retained austenite during straining. The polygonal fenite behavior during straining depends on dislocation substructure tonned due to the deformation and the additional mobile dislocations caused by the TRIP effect. TRIP and TWIP effects depend not only on the chemical and mechanical stability of retained austenite, but also on the interaction of the phases during straining.<br /

Research Notes : U.S.S.R. : Subunit composition of glycinin from various samples of cultivated and wild soybean

The major storage protein of llS class of soybean seeds, glycinin, has a complex subunit structure. Each of the six subunits is composed of two pro-tein molecules (acidic and basic), linked via disulphide bonds (Badley et al., 1975). Depending on subunit, the acidic moiety molecular weight varies from 37,000 to 42,000, with one exception (m.w. 10,000)

Experimental approaches to the assessment of potential cardioprotective means with doxorubicin-associated cardiomyopathy

Development of methodological approaches for evaluation of cardioprotective activity of drugs in doxorubicin cardiomyopath

Evaluation of cardioprotective effects of the incritinmimetics exenatideand vildagliptin in the experiment

The results of experimental and clinical trials make it clear that incretin mimetics possess pleiotropic effects and demonstrate the value in terms of assessment of their potential opportunities as cardioprotectors. Goals: To study the cardioprotective effects of exenatide and vildagliptin on the model of doxorubicin-induced cardiomyopath

Uloga dodataka Cr i P u razvoju mikrostrukture i teksture u žarenim niskougljičnim čelicima

The recrystallisation behaviour of four warm rolled steels was investigated during annealing. The extra-low carbon (ELC) steel displayed the highest rate of recrystallisation, the steels with additions of chromium and phosphorus (LC(Cr)), (LC(Cr,P)) recrystallised at intermediate rates, while the interstitial-free (IF) steel exhibited the lowest rate. The additions of Cr and Cr/P increased the fraction of g-fibre in the annealing textures compared to that present in the ELC steel; this effect was particularly pronounced up to 50 % recrystallisation. After the completion of recrystallisation, the steel textures were characterized by a dominant g-fibre in the IF steel, while in the three LC steels, the RD fibre was the principal one.Ispitivana je rekristalizacija četiri tipa toplo valjanih čelika tijekom žarenja. Čelik s ekstra niskim ugljikom (ELC) pokazao je najveću brzinu rekristalizacije, čelici s dodatkom kroma i fosfora (LC(Cr)), (LC(Cr,P)) pokazali su srednje brzine rekristalizacije, dok je intersticijski-slobodan čelik (IF) imao najmanju brzinu. Dodavanje Cr i Cr/P povećalo je frakciju -vlaknastog materijala u žarenim teksturama u usporedbi s onom koju susrećemo u ELC čeliku; taj efekt je posebno izražen u 50 %-postotnoj rekristalizaciji. Nakon završetka rekristalizacije, teksture čelika su obilježene dominacijom -vlaknastog tkiva u IF-čeliku, dok je u tri LC čelika RD-vlakno bilo glavno

The effect of Nb, Mo, and A1 additions on the transformation behaviour and mechanical properties of thermomechanically processed C-Si-Mn trip steel

The effect of additions of Nb, A1 and Mo to Fe-C-Mn-Si TRIP steels on the final microstructure and mechanical properties after simulated thermomechanical processing (TMP) has been studied. Laboratory simulations of continuous cooling during TMP were performed using a quench deformation dilatometer, while laboratory simulations of discontinuous cooling during TMP were performed using a hot rolling mill. From this a comprehensive understanding of the structural and kinetic aspects of the bainite transformation in these types of TRIP steels has been developed. All samples were characterised using optical microscopy and XRD. The relationships between the morphology of bainitic structure, volume fraction, stability of RA and mechanical properties were investigated.<br /