Effect of Mg addition on strengthening of aluminium alloys subjected to different strain paths in high pressure torsion

The effect of Mg addition on strengthening of aluminium alloys was studied by monotonic, cyclic and single reversal deformation in high pressure torsion. The results show the extent of strengthening varies between these three processing methods and are dependent on Mg content. There is a relatively low hardness increment in commercially pure aluminium, slightly higher hardness increment in an Al–1Mg alloy and significant hardness increment in an Al–2Mg alloy. The difference of strengthening due to strain paths is discussed in terms of geometrically necessary dislocations.