On the recrystallization and texture of Fe-36%Ni alloy after accumulative roll bonding and annealing at 600 °C

Microstructure and texture evolution of Fe-36%Ni (wt.%) alloy after 1, 5 and 10 accumulative roll-bonding (ARB) cycles and annealing at 600 °C up to 3600 seconds were studied using electron backscatter diffraction. Microstructural and textural changes after ARB and annealing were compared to those existing in the literature after conventional rolling. The microstructure was not stable at 600 °C for all ARB samples even after 3600 seconds of annealing. The recrystallization texture was dominated by the Cube {001} texture component. Recrystallization kinetics were determined using microhardness measurement and were close to those after cold rolling with Avrami time exponent around unity. The texture evolution at high strain was discussed in terms of grain boundary migration obstruction by the formation of layer interfaces and small recrystallized grains near the bonded interfaces

Optimization of microstructural evolution during laser cladding of Ni based powder on GCI glass molds

International audienceIn the glass industry, laser cladding is an innovative surfacing technique of depositing a layer of nickel to protect glass mold against corrosion, abrasion and thermal fatigue. This method (powder fusion by projection), well known in additive manufacturing represents a real technological leap for the glass industry. However, during laser cladding of Ni-based powder on gray cast iron, cracks can be observed for some process conditions. These cracks are often due to the Heat Affected Zone which creates structural stresses linked to the development of a martensitic structure in the ferritic matrix of the lamellar graphite cast iron. The aim of this work is to observe the impact of laser cladding (without substrate pre-heating usually used to limit cracking) on coating behavior but also on flake-graphite cast iron substrates. The microstructure and the mechanical properties were studied around the interface cladding/substrate. The impact of the processing parameters (power P, scanning speed v and powder feeding rate PFR was studied by using the ANOVA (ANalysis Of VAriance) technique. It has been observed that laser cladding on graphite cast iron without cracking is possible by limiting the linear energy induced by the process. Optimization of the processing parameters in order to obtain the industrial expected geometry of the coating has also been proposed

Microstructure, Texture, and Mechanical Properties of Ni-W Alloy After Accumulative Roll Bonding

International audienceIn this study, the microstructure, texture, and mechanical properties evolution of Ni-14W (wt. %) alloy processed up to four cycles of accumulative roll-bonding (ARB) were investigated using electron backscatter diffraction, microhardness measurements, and tensile tests. The initial equiaxed grains, with an average size of 10 μm, underwent a strong refinement after ARB processing. The elongated ultrafine grains were parallel to the rolling direction, with a grain thickness of 0.2 µm. The texture after ARB processing was characterized by the typical rolling components (Copper, S and Brass), which showed a tendency toward stabilization after four cycles. The microhardness increased substantially (+86%) and seemed to saturate after three cycles. The tensile tests demonstrated that Ni-14W samples subjected to ARB processing exhibited high strength (> 1200 MPa after three ARB cycles) and very poor ductility

Recrystallization and grain growth at the interface of a bimetallic colaminated strip composed of two different Fe-Ni alloys

International audienceRoll bonding is a solid-state welding process widely used to manufacture layered metal composites. Particular properties may thus be obtained using the physical features of each material of the composite. Bimetal plates consisting of two different Fe-Ni alloys were made by roll bonding followed by heat treatment for 90 minutes at various annealing temperatures. The effects of post-rolling heat treatments on the bonding strength of a bimetal strip were investigated in relation to the interface microstructure evolution. Both recrystallization and grain growth took place at the interface during annealing. In particular, nucleation of new grains as well as growing grains crossing the interface may have contributed to the improvement of the bonding strength. Moreover, diffusion through the interface was found to drastically enhance the bonding strength from 850°C up to 1050°C. However, excessive grain growth associated to porosity occurrence probably caused the saturation of the bonding strength beyond 1050°C

Investigation of microstructure and texture evolution of a Mg/Al laminated composite elaborated by accumulative roll bonding

International audienceThe microstructure and texture of an Al1050/AZ31/Al1050 laminated composite fabricated by accumulative roll bonding at 400 °C up to 5 cycles are investigated using Electron BackScatter Diffraction, neutron diffraction, microhardness measurements and tensile tests. EBSD analysis has shown that ARB processing led to microstructural refinement with equiaxed grain microstructure in AZ31 layers and to the development of elongated grains parallel to the rolling direction in Al 1050 layers. No new phases formed at the bond interface after the first ARB cycle while Mg17Al12 and Mg2Al3 phases appeared after subsequent cycles. During the ARB processing, a typical strong basal (0002) texture is observed in AZ31 layers along with a weak rolling texture showed in Al 1050 layers with a dominant Rotated Cube {001}〈110〉 component. The microhardness of Al1050/AZ31/Al1050 laminated composite increased with increasing ARB cycles and almost saturated after five ARB cycles. The yield strength and ultimate strength increased gradually between 1 and 3 ARB cycles due to the strain hardening and grain refinement. They decreased with further increasing of the ARB cycles because of crack and failure of the MgxAly intermetallic compounds which developed during 4th and 5th ARB cycles. The deformation behavior of the laminated composite becomes rather similar to the behavior of AZ31 alloy that underwent a dynamic recrystallization during processing

Thermal Stability of an Mg‐Nd Alloy Processed by High‐Pressure Torsion

The evolution of microstructure, texture and mechanical properties of an Mg‐1.43Nd (wt.%) alloy are investigated after processing by high‐pressure torsion at room temperature through 5 turns and isochronal annealing for 1 h at 150, 250, 350 and 450 °C using Electron BackScatter Diffraction and Vickers microhardness. The alloy exhibits a good thermal stability up to an annealing at 250 °C, with mean grain size of ≈0.65 μm. The microhardness shows an initial hardening after annealing at 150 °C and then a subsequent softening. The deformation texture, a basal texture shifted 60° away from the shear direction (SD), is retained during annealing up to 250 °C. By contrast, a basal texture with symmetrical splitting towards SD is developed after annealing at 350 °C. The precipitation sequence and their pinning effect are responsible for the age‐hardening, stabilization of grain size and the texture modification. The kinetics of grain growth in the Mg‐1.43Nd alloy follows two stages depending on the temperature annealing range, with an activation energy of ≈26 kJ/mol in the low temperature range of 150–250 °C and ~147 kJ/mol in the high temperature range of 250–450 °C

Régime sans gluten

Tuberculosis, despite its prevention, remains an endemic affection in Morocco. Although rare, pseudo surgical forms and especially peritonitis are mainly due to delayed diagnosis. We report the case of a 30-year-old woman, admitted for peritonitis. The diagnosis of tuberculous peritonitis was established during surgery with macroscopic observation of granulations, and confirmed after biopsy specimens by identification of a giant lymph node cell granuloma with caseous necrosis. Outcome was favorable after appropriate antibiotic therapy. This observation emphasizes the fact that peritonitis, although a rare complication of peritoneal tuberculosis, poses problems of positive and differential diagnosis. Even if treatment is based on antituberculous quadritherapy, surgery is sometimes necessary and should be decided in due time

La cristallographie appliquée à l’EBSD

International audienc

Feco alloy, fesi alloy or fe sheet or strip and production method thereof, magnetic transformer core produced from said sheet or strip, and transformer comprising same

The invention relates to a cold-rolled, annealed ferrous alloy sheet or strip (1), characterised in that it consists of (by weight percentage): traces ≤ Co ≤ 40%; if Co ≥ 35%, traces ≤ Si ≤ 1.0%; if traces ≤ Co < 35%, traces ≤ Si ≤ 3.5%; if traces ≤ Co < 35%, Si + 0.6 %Al ≤ 4.5 - 0.1 %Co; traces ≤ Cr ≤ 10%; traces ≤ V + W + Mo + Ni ≤ 4%; traces ≤ Mn ≤ 4%; traces ≤ Al ≤ 3%; traces ≤ S ≤ 0.005%; traces ≤ P ≤ 0.007%; traces ≤ Ni ≤ 3%; traces ≤ Cu ≤ 0.5%; traces ≤ Nb ≤ 0.1%; traces ≤ Zr ≤ 0.1%; traces ≤ Ti ≤ 0.2%; traces ≤ N ≤ 0.01 %; traces ≤ Ca ≤ 0.01 %; traces ≤ Mg ≤ 0.01%; traces ≤ Ta ≤ 0.01%; traces ≤ B ≤ 0.005%; traces ≤ O ≤ 0.01%; the remainder being iron and impurities resulting from production. The sheet or strip is also characterised in that, for 1.8 T induction, the maximum deviation (Max ∆λ) between the magnetostriction deformation values λ, which are measured both parallel to the magnetic field (Ha) applied (λ//H) and perpendicularly to the magnetic field (Ha) applied (λ⊥H) over three rectangular samples (2, 3, 4) of the sheet or strip, of which the large sides are parallel to the sheet or strip rolling direction (DL), parallel to the cross direction (DT) of the sheet or strip, and parallel to the direction forming an angle of 45° with the rolling direction (DL) and the cross direction (DT), is at most 25ppm. The sheet or strip is further characterised by its recrystallisation rate of between 80 à 100%. The invention also relates to a method for producing such a sheet or strip, a magnetic transformer core produced using said sheet or strip, and a transformer comprising same

Feco alloy, fesi alloy or fe sheet or strip and production method thereof, magnetic transformer core produced from said sheet or strip, and transformer comprising same

The invention relates to a cold-rolled, annealed ferrous alloy sheet or strip (1), characterised in that it consists of (by weight percentage): traces ≤ Co ≤ 40%; if Co ≥ 35%, traces ≤ Si ≤ 1.0%; if traces ≤ Co < 35%, traces ≤ Si ≤ 3.5%; if traces ≤ Co < 35%, Si + 0.6 %Al ≤ 4.5 - 0.1 %Co; traces ≤ Cr ≤ 10%; traces ≤ V + W + Mo + Ni ≤ 4%; traces ≤ Mn ≤ 4%; traces ≤ Al ≤ 3%; traces ≤ S ≤ 0.005%; traces ≤ P ≤ 0.007%; traces ≤ Ni ≤ 3%; traces ≤ Cu ≤ 0.5%; traces ≤ Nb ≤ 0.1%; traces ≤ Zr ≤ 0.1%; traces ≤ Ti ≤ 0.2%; traces ≤ N ≤ 0.01 %; traces ≤ Ca ≤ 0.01 %; traces ≤ Mg ≤ 0.01%; traces ≤ Ta ≤ 0.01%; traces ≤ B ≤ 0.005%; traces ≤ O ≤ 0.01%; the remainder being iron and impurities resulting from production. The sheet or strip is also characterised in that, for 1.8 T induction, the maximum deviation (Max ∆λ) between the magnetostriction deformation values λ, which are measured both parallel to the magnetic field (Ha) applied (λ//H) and perpendicularly to the magnetic field (Ha) applied (λ⊥H) over three rectangular samples (2, 3, 4) of the sheet or strip, of which the large sides are parallel to the sheet or strip rolling direction (DL), parallel to the cross direction (DT) of the sheet or strip, and parallel to the direction forming an angle of 45° with the rolling direction (DL) and the cross direction (DT), is at most 25ppm. The sheet or strip is further characterised by its recrystallisation rate of between 80 à 100%. The invention also relates to a method for producing such a sheet or strip, a magnetic transformer core produced using said sheet or strip, and a transformer comprising same