Effect of rolling geometry on the mechanical properties,microstructure and recrystallization texture of Al-Mg-Si alloys

The effect of rolling geometry on mechanical properties, microstructure, and recrystallization texture of Al-Mg-Si alloys was studied by means of tensile tests, microstructural observations, and electron backscatter diffraction measurements. The results reveal that the elongation and the average plasticity strain ratio (r) values of the T4P (pre-aging plus natural aging)-treated alloy sheet with a rolling geometry value between 1 and 3 are somewhat higher than those of the T4P-treated sheet with a rolling geometry value between 3 and 6. The deformation and recrystallization microstructures of the sheet with a rolling geometry value between 1 and 3 are more uniform than those of the sheet with a rolling geometry value between 3 and 6. The former also possesses somewhat higher surface quality. H {001}〈110〉 and Goss {110}〈001〉 orientations are the main recrystallization texture components for the former case, whereas the latter case only includes H{001}〈110〉 orientation. Texture gradients are present in the two alloy sheets. Shear texture component F on the surface of the sheet with a rolling geometry value between 3 and 6 and its higher texture gradients have revealed that non-uniform deformation occurred during cold rolling. The effects of texture on the yield strength and r value were also discussed.     

Effect of micro-alloying Ca on microstructure,texture and mechanical properties of Mg-Zn-Y-Ce alloys

Microstructure,texture and mechanical properties of Mg-5 Zn-0.3 Y-0.2 Ce alloys with the addition of trace xCa(x=0,0.3,0.6 wt%) were systematically investigated in this work.The results revealed that more secondary eutectic phases and smaller grain size of as-cast microstructure could be found with increasing Ca content.After hot extrusion,the Ca-free alloy showed a uniformly recrystallized grain structure,while the Ca-containing alloys possessed a bimodal grain structure composed of fine dynamic recrystallized(DRXed) grains with a size of several microns and un-recrystallized coarse grains.EBSD analysis showed that the three extruded alloys had a fiber texture of(0001) basal plane aligned with the extrusion direction.Texture intensity of the DRXed region was weaker than the deformed region.The extruded alloy with the addition of 0.6 wt% Ca exhibited the highest yield strength of 321 MPa due to the smallest DRXed grain size,the deformed region with strong basal texture and dense nanosized precipitates.