EFFECT OF COMPOSITION ON CRYSTALLOGRAPHIC TEXTURE IN HOT-ROLLED AL-LI-CU ALLOYS

The hot-rolling textures of ternary Al-Li-Cu alloys have been characte rized to determine their effects on the yield strength anisotropy. The alloys used in the study had (Li/Cu) ratios varying from 0 to infinit y and were hot-rolled in the 520-400 degrees C temperature range. All the alloys showed well developed beta-fibers, with a maximum intensity at Brass, and a weak background of alpha-fiber. The Brass components were very strong for the alloys with intermediate (Li/Cu) ratios that had relatively more T-1 precipitates in the microstructure compared wi th other alloys. In addition, all compositions showed a weak Cube or r elated Cube recrystallization texture components. The observed texture s are attributed to the effects of constrained deformation during hot deformation. The texture results were used to predict the yield streng th anisotropies in the alloys. The predictions were in agreement with the experimental results for the high (Li/Cu) alloys. However, in the low (Li/Cu) alloys, the discrepancies between the predicted and the me asured yield strength anisotropies can be attributed to a modifying ef fect of the directional platelet precipitates on deformation.