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

The Microstructure, Texture and Mechanical Properties of Friction Stir Welded Aluminum Alloy

International audienceThe microstructure and texture of 7075˗T6 FSW weld with optimal parameters were investigated using optical microscopy, electron back scatter diffraction and neutron diffraction. The mechanical properties were also characterized through microhardness, nanoindentation and ultrasonic tests. The friction stir welding was performed at a nominal rotational speed of 1400 rpm and a traverse speed of 60 mm/min. The nugget zone contained fine, equiaxed and fully recrystallized grains. The texture of the base material mainly consisted of Cube and rotated Goss components. However in the nugget zone, the dominant texture components were B and B ̅ among common shear orientations. Elastic modulus was measured by ultrasonic and nanoindentation methods. The ultrasonic one has the main advantageous to be nondestructive, easy, inexpensive and fast. A little increase of Young modulus is observed in nugget zone compared to base metal