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The texture evolution in the intermediate (the 1/4 thickness) layer of hot-rolled Al-Cu-Mg alloy sheets was investigated by the x-ray diffraction technique, electron backscattered diffraction analysis and transmission electron microscopy observation. The results showed that a texture transition from the shear texture {001} to the β-fiber textures occurred as the rolling temperature increased to 420 °C. The shear strain caused by friction resulted in this strong shear texture formation at the low rolling temperature. As the rolling temperature increased, the plane strain substituting the shear strain dominated in the intermediate layer, giving rise to a significant increase in the β-fiber textures. Increasing the rolling temperature was found to preferentially activate the non-octahedral {112} slip system, thereby benefiting the development of strong Brass. At the low rolling reduction of 74%, the textures with low intensity tended to converge on the α-fiber, containing Goss, Brass, P and L components. As the rolling reduction increased to 90%, the textures were strengthened and gradually flew toward the β-fiber, containing Brass, Copper and S components. The S and Copper bands were found to be the preferential sites for the development of recrystallizing Cube grains during hot rolling.

Texture and microstructure development of Al-4Cu-1.6Mg alloy during hot rolling was examined by using XRD, EBSD and TEM. The results showed that starting with a random texture during the early stages of rolling with reduction lower than 58.9% at blooming temperature of 430 °C, the materials developed a typical α-fiber texture in the center layer as deformation reduction reached 75.7%. And then the α-fiber textures in the center layer rotated into Brass component mainly through the activity of {111} slip system as the reduction reached 96.3%. Different from the center textures, the main texture in the surface layer was r-Cube with 96.3% reduction. The increase in rolling temperature was beneficial for the enhanced texture intensity of Brass component in the center layer. The analysis of substructure energy density indicated that Brass subgrain had a lower substructural energy density than other oriented subgrains, which together with increased slip rate at elevated temperature, contributed to the development of center Brass texture.

The effect of intensifying Goss texture and refining Goss grains on the enhancement of fatigue crack propagation (FCP) resistance in an Al-Cu-Mg alloy was systematically investigated. The way to improve fatigue performance mainly includes two steps: intensifying Goss texture component and then refining these Goss grains. Hot rolling at elevated temperature and pre-solution treatment are capable of Goss texture formation. Then large cold rolling reduction can refine grains and obtain more these Goss grains, which increases the twist angle boundary components with their adjacent grains to enhance fatigue crack deflection and FCP resistance. By contrast, refining Brass etc. rolling-oriented grains can increase the tilt angle boundary components and promote fatigue crack growth. And the reason why grain refinement cannot always improve fatigue properties in alloys with micrometer grains can depend mainly on grain orientations and the relative boundary components in this Al-Cu-Mg alloy. Besides, coarse Fe-, Si- and Mn-rich inclusions are detrimental to fatigue properties, but the fine, globular and homogeneous distribution of these particles can improve fatigue properties to some extent.

Semi-continuous cast Mg–8Gd–3Y–0.4Zr (wt%) alloy in different conditions was systematically investigated in its microstructure and mechanical properties. β phase and eutectic compounds were observed in the as-cast alloy. β phase and most of the eutectic compounds were dissolved into the matrix and Y-rich phase was precipitated during the homogenization. Extreme grain refinement and slight precipitation took place in the extrusion of the alloy. β′ phase precipitates were observed and studied in the peak-aged alloy. Effective strengthening modes were used to predict the strength and the results are consistent with the experiment. The results suggest that solution strengthening and grain boundary strengthening are the main strengthening factors of the as-extruded alloy, while β′ phase is the biggest strengthening contributor of the as peak-aged alloy.