CC9 Livestock-Associated Staphylococcus aureus Emerges in Bloodstream Infections in French Patients Unconnected With Animal Farming

We report 4 bloodstream infections associated with CC9 agr type II Staphylococcus aureus in individuals without animal exposure. We demonstrate, by microarray analysis, the presence of egc cluster, fnbA, cap operon, lukS, set2, set12, splE, splD, sak, epiD, and can, genomic features associated with a high virulence potential in human

Evolution of microstructure and crystallographic texture during dissimilar friction stir welding of duplex stainless steel to low carbon-manganese structural steel

Electron backscattered diffraction (EBSD) was used to analyze the evolution of microstructure and crystallographic texture during friction stir welding of dissimilar type 2205 duplex stainless steel (DSS) to type S275 low carbon-manganese structural steel. The results of microstructural analyses show that the temperature in the center of stirred zone reached temperatures between Ac 1 and Ac 3 during welding, resulting in a minor ferrite-to-austenite phase transformation in the S275 steel, and no changes in the fractions of ferrite and austenite in the DSS. Temperatures in the thermomechanically affected and shoulder-affected zones of both materials, in particular toward the root of the weld, did not exceed the Ac 1 of S275 steel. The shear generated by the friction between the material and the rotating probe occurred in austenitic/ferritic phase field of the S275 and DSS. In the former, the transformed austenite regions of the microstructure were transformed to acicular ferrite, on cooling, while the dual-phase austenitic/ferritic structure of the latter was retained. Studying the development of crystallographic textures with regard to shear flow lines generated by the probe tool showed the dominance of simple shear components across the whole weld in both materials. The ferrite texture in S275 steel was dominated by D 1, D 2, E, E¯ , and F, where the fraction of acicular ferrite formed on cooling showed a negligible deviation from the texture for the ideal shear texture components of bcc metals. The ferrite texture in DSS was dominated by D 1, D 2, I, I¯ , and F, and that of austenite was dominated by the A, A¯ , B, and B¯ of the ideal shear texture components for bcc and fcc metals, respectively. While D 1, D 2, and F components of the ideal shear texture are common between the ferrite in S275 steel and that of dual-phase DSS, the preferential partitioning of strain into the ferrite phase of DSS led to the development of I and I¯ components in DSS, as opposed to E and E¯ in the S275 steel. The formations of fine and ultrafine equiaxed grains were observed in different regions of both materials that are believed to be due to strain-induced continuous dynamic recrystallization (CDRX) in ferrite of both DSS and S275 steel, and discontinuous dynamic recrystallization (DDRX) in austenite phase of DSS

Nano titanium carbide particle reinforced aluminumcomposite materials prepared by ball milling followed by reactive sintering

International audienceThe development of the aviation industry requires the use of new metallic materials with superiorspecific mechanical properties compared to existing materials. In particular, the metal matrix composites (MMC) reinforced by nano-particles draw attention due to their excellent machinability.However, it is well-known that handling nanoparticles in industry is problematic due to respect of safety rules regarding nanomaterials. In order to overcome this problem, we have demonstrated the feasibility to fabricate nanocomposite materials without using any starting nanoparticles. We studied the ternary system aluminum/carbon/titanium for which we have shown the possibility to create the nanoparticles of titanium carbide by a flash sintering. So, we fabricated the titanium carbide (TiC) nano particles reinforced aluminum matrix (Alnano TiC) composite, and demonstrated that the size of TiC nanoparticles could be controlled by both heating rate and dwell temperature. We observed avery narrow size distribution of particles, ranging from 25 to 90 nm. Observation by transmission electron microscopy revealed that the TiC nanoparticles were individually distributed in Alnano TiC composite and that the Al/nano TiC interface was intimate. Tensile tests have been performed on specimens with various TiC contents. It was found that the ultimate tensile strength of the Al34 vol percent nano TiC composite was higher than 600 MPa with a failure elongation of 4.2 percent. The observed ridge of pure Al on the fracture surface implies that pure Al contributes to the conservation of a remarkable failure elongation of the Al;nano TiC composite. The elongation reaches 7.2 percent with the TiC volumefraction of 27 percent

Dependency of recrystallization mechanism to the initial grain size

The effect of initial grain size on the recrystallization behavior of a type 304 austenitic stainless steel during and following hot deformation was investigated using hot torsion. The refinement of the initial grain size to 8 μm, compared with an initial grain size of 35 μm, had considerable effects on the dynamic recrystallization (DRX) and post-DRX phenomena. For both DRX and post-DRX, microstructural investigations using electron backscattered diffraction confirmed an interesting transition from conventional (discontinuous) to continuous DRX with a decrease in the initial grain size. Also, there were unexpected effects of initial grain size on DRX and post-DRX grain sizes