Characterisation of Microstructure, Texture and Mechanical Properties of Pure Aluminium Sheets Severely Deformed by Constrained Groove Pressing and Subsequent Cold Rolling

The present investigation reports on microstructure and mechanical behaviour in high-purity aluminium sheets processed by combined constrained groove pressing and cold rolling. Annealed high-purity aluminium constrained groove pressed up to 3 cycles and 4 cycles is subjected to post cold rolling of 60% and 90% thickness reductions. Electron backscattered diffraction studies revealed superior grain refinement of similar to 1.86 mu m after 4 cycles of constrained groove pressing. Constrained groove pressing when combined with cold rolling resulted in additional grain refinement. Further, grain boundary characteristics after constrained groove pressing and combined constrained groove pressing and cold rolling indicates development of substantial fractions of low-angle grain boundaries. Examination of tensile behaviour after constrained groove pressing process shows its effectiveness in considerable improvement in ultimate tensile strength of material by a factor of 4.6. Meanwhile, deformation with cold rolling enhanced ultimate tensile strength, maximising to around 225 MPa from 22.4 MPa in the as received state. Crystallographic texture represented by orientation distribution function plots revealed the evolution of major face centred cubic ideal rolling texture components after severe plastic deformation during constrained groove pressing and post rolling after constrained groove pressing process.