| Evolution of textures and microstructures during rolling of commercial purity Al and Al-Mg alloys, including 99.99% Al, AA 1100 strip cast alloy, AA 3002 DC cast alloy, AA 5052 DC cast alloy, AA 5052 strip cast alloy, AA 5017 strip cast alloy, and AA 5182 DC cast alloy, is studied. The texture development is quantitatively analyzed by means of the three dimensional orientation distribution functions (ODFs) and the microstructure evolution is observed by light microscopy and transmission electron microscopy (TEM).; The experimental procedures consist of both hot and cold rolling of materials under different pre-treated conditions. For hot rolling, it is observed that the development of microstructures and textures is associated not only with the deformation mechanism but also, if dynamic recrystallization (DRX) occurs, with the dynamic restoration mechanism involved. The experimental results indicate that as the Mg concentration increases the strain at which DRX occurs decreases. At a strain of 0.92, a mean strain rate of 6.13 (s{dollar}sp{lcub}-1{rcub}{dollar}) and a rolling temperature of 510{dollar}spcirc{dollar}C, the dynamic restoration mechanism for commercial purity Al is dynamic recovery (DRV), for AA 5052 alloy (2.36%Mg) is partial DRX, but for AA 5182 alloy (4.36%Mg) is DRX. At the same temperature DRX occurs for commercial purity Al at a strain of 2.30 and a mean strain rate of 12.48 (s{dollar}sp{lcub}-1{rcub}{dollar}). It is confirmed by the ODF analysis that for dynamically recrystallized materials the deformation texture is randomized.; For cold rolling, the texture development is mainly associated with the deformation mechanism. For commercial purity Al, the Cu and S texture components are mainly developed during deformation. For Al-Mg alloys, as solute supersaturation which consists mainly of magnesium increases the Brass texture component increases. When large amounts of Mg containing precipitates are formed, on the other hand, the formation of deformation zones around precipitates results in large misorientations and thus weakens the deformation texture.; In addition, the Taylor-Bishop-Hill (TBH) model (full constraints) which gives an upper bound for the yield stress is used to evaluate the plastic anisotropy caused by the preferred grain orientation. A ratio of {dollar}Delta{dollar}R/R is determined by the TBH model coupled with ODFs as weight functions. It is found that this ratio is quantitatively correlated to the earing value of a textured Al or Al-Mg alloy sheet. As strain increases the earing value increases proportionally to the increase of the predicted R ratio, which indicates an approximate linear correlation. |
