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

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

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

Neutron diffraction versus EBSD analysis of the texture in Fe-36%Ni alloy after accumulative roll bonding

35-44The texture evolution of Fe-36%Ni(wt%) alloy processed by accumulative roll-bonding (ARB) up to six cycles was investigated using neutron diffraction. The texture sharpened after the second cycle, showed continuous strength up to six cycles, and was characterized by the typical copper-type texture together with a R-Cube{001} component that appeared after two cycles of ARB processing. The texture obtained by neutron diffraction was compared with that measured by electron backscatter diffraction (EBSD). The neutron diffraction and EBSD texture intensities were substantially similarand exhibited almost the same trends for all texture components. The evolution of the Lankford coefficient R, average Lankford factor , planar anisotropy ΔR, and Young modulus values versus angle to rolling direction calculated from experimental textures of ARBed samples showed that ARB processing increased the plastic anisotropy and Young modulus of the sheet

An EBSD analysis of Fe-36%Ni alloy processed by HPT at ambient and a warm temperature

Electron backscatter diffraction (EBSD) was used to evaluate the evolution of microstructure and texture in an Fe-36%Ni (wt. %) alloy after processing by high-pressure torsion (HPT) up to 10 turns at ambient temperature and 250 °C. HPT processing led to a strong microstructural refinement with average grain sizes of ~ 0.30 and ~ 0.24 μm at ambient temperature and 250 °C, respectively. The high-angle grain boundary fraction was slightly higher after processing at 250 °C and gradually increased with increasing numbers of HPT turns to saturate after 5 turns. The crystallographic texture after HPT processing at ambient temperature was characterized by typical A and B fibers of a simple shear FCC texture with domination of the B component. By contrast, the A, B and C components developed during HPT processing at 250 °C with C as the dominant texture component. The microhardness values for both HPT deformation conditions were very similar with a continuous increase with increasing HPT turns and almost saturation after 5 HPT turns. The grain size dependence of the microhardness followed the Hall-Petch relationship. The explanation for the microstructure, texture and microhardness difference was attributed to a dynamic recovery process that operates during processing at 250 °C