A study of the bauschinger effect in AlCu alloys

The Bauschinger effect has been used to study the strain hardening in a two phase alloy. AlCu alloys aged to θ′ condition have been examined as both polycrystals and single crystals. The single crystals were oriented for slip on different slip systems. The development of the long range back stress has been studied, together with its dependence on strain, temperature and orientation.The magnitude of the back stress at small strains, including its temperature and orientation dependence, has been accounted for using the unrelaxed model proposed by Brown and Clarke. At larger strains the saturation of the back stress is caused by a relaxation process, which is shown to be the cutting of the θ′ particles by matrix dislocations.In an Appendix the data reported by Russell and Ashby from compression tests on AlCu-θ′ alloys are examined to determine if they are also consistent with back stress models.