On the microstructure and texture of Cu-Cr-Zr alloy after severe plastic deformation by ECAP

Samples of a commercial Cu-1Cr-0.1Zr (wt.%) alloy were subjected to severe plastic deformation at room temperature using equal-channel angular pressing (ECAP) up to 16 passes via route Bc. The microstructure and texture of the processed samples were analyzed through electron backscatter diffraction (EBSD). Most of the grains were more or less inclined in the direction of shearing (45° from the extrusion direction) and substantially refined. The deformation structure evolved from elongated grains to a duplex equiaxed-elongated microstructure upon straining. The fraction of high angle boundaries gradually increased with the number of passes up to 70%. The texture after ECAP was mainly of ECAP shear type whose components shifted slightly from their ideal positions. A net strengthening and stabilization of the B/View the MathML sourcecomponents were observed.Peer ReviewedPostprint (author's final draft

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

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

Microstructure and texture evolution of AZ31 Mg alloy after uniaxial compression and annealing

The effect of initial texture on the microstructure and texture evolution of as extruded AZ31 alloy after hot uniaxial compression at 430 °C and subsequent annealing at 450 °C for 72h has been investigated using electron backscatter diffraction. Samples were machined from the extruded block in such orientations that the compression axis, CD, was parallel (CD0ED) or perpendicular (CD90ED) to the initial extrusion direction, ED, respectively. Results show that the deformation microstructure for both samples was characterized by equiaxed grains that resulted from dynamic recrystallization. Annealing at 450 °C for 72 h led to the increase of grains size to 28 and 25 µm for CD0ED and CD90ED samples, respectively. A random deformation texture was developed in CD0ED sample while the deformation of CD90ED developed typical (0002) basal texture. The deformation textures of both samples were retained after subsequent annealing at 450 °C for 72 h. The flow behavior was affected by the initial texture. The CD0ED sample showed the highest work hardening. These evolutions were explained in term of the activation and suppression of basal, non-basal slip and mechanical twinning. Keywords: Magnesium alloys, Schmid factor, Texture, Deformation, Annealing, Microstructur

Texture evolution in high-pressure torsion processing

Among the severe plastic deformation processing (SPD) of materials, high-pressure torsion (HPT) is known to induce considerable amounts of plastic strain and crucial grain refinement up to the nanometer scale. There have been several reviews on the mechanical properties and/or microstructure correlations of SPD-processed materials published during the last two decades. By contrast, a review on the crystallographic texture evolution during HPT processing is not at present available. Consequently, this work was undertaken to review the texture evolution in Face-Centered Cubic (FCC), Body-Centered Cubic (BCC) and Hexagonal Close-Packed (HCP) crystal structure materials processed exclusively by HPT with a special emphasis on the influence of many intrinsic and extrinsic factors such as the imposed strain, the deformation temperature and the alloying elements

Investigation of recrystallization kinetics by DSC analysis of Mg-Ce alloy after severe plastic deformation

The recrystallization process of Mg-Ce alloy after high-pressure torsion (HPT) was investigated using differential scanning calorimetry (DSC) technique. The DSC results show that the recrystallization peak temperature increases with increasing the heating rate which confirms that recrystallization is thermally activated and kinetically controlled. The recrystallized volume fraction, the rate of recrystallization, the transformation function and the kinetic parameters (activation energy and Avrami exponent) for Mg-Ce alloy were estimated using several analytical approaches

Accumulative Roll Bonding at Room Temperature of a Bi-Metallic AA5754/AA6061 Composite: Impact of Strain Path on Microstructure, Texture, and Mechanical Properties**

International audienceAccumulative roll bonding (ARB) is performed at room temperature on an aluminum composite up to five rolling cycles, using two different paths: the conventional one (ARB) and the cross ARB (CARB) one consisting of a 90 rotation of the rolling direction before each rolling pass. The microstructure is refined faster by CARB than by ARB occasioning higher yield strength of the elaborated samples. Besides, CARB has the ability to delay the loss of stratification of the composite. The resulting textures are different: while ARB promotes typical rolling components (Brass {011}, Goss {110}, Dillamore {4 4 11}), S {123}), CARB promotes the ND-rotated Brass {011} instead of Brass together with the S and Dillamore components. A Visco-Plastic Self-Consistent (VPSC) simulation highlights that the ND-rotated Brass had Brass and S components for origin. The ND-rotated Brass presence in the texture promotes a better mechanical isotropy of the composite sheet