Significance of Deformation Mode in Hot Deformation

In order to study strain path effects, hot deformation tests must be carried out utilising different combinations of compressive, tensile and shear strains. However, before the results from these tests can be reliably interpreted, it is important to carry out deformations in simple tension, compression and torsion as a 'baseline'. Differences in deformation mode affect the deformed grain shape and grain boundary area. The slip systems activated during, for example, torsion and compression will also be different, this leads to differences in final textures and substructural morphology. The macroscopic consequence of these is that flow stress and recrystallisation kinetics are dependent on deformation mode. An important issue which needs to be addressed is whether the micro- / macro-structural response of a material to complex strain histories can be predicted using simple additive functions of the baseline data. This initial round of tests was conducted on an Al-Mg-Mn-Si alloy.