Investigating Bauschinger Effect in the Autofrettaged Tubes made of 7075 Aluminum Alloy using Experimental Data

A7075 aluminum alloy is considered as a high-strength alloy which is used making under-pressure tubes according to ASTM B210M–05 standard. Finding an appropriate model for investigating Bauschinger effect factor in A7075 aluminum alloy behavior plays an important role analyzing the process of autofrettaged tubes. For this purpose، the results of experimental data of uniaxial tension- compression tests have been used. In order to carry out the tests، an Instron servo-hydraulic machine has been used. The samples were made having 12. 5 mm based on ASTM standard E8M-97a. The fact that plastic strain created in these alloys is considered as unloading characteristic، to model the material behavior، the series of these tests on the basis of plastic deformation is done differently. In this research، tests were done at plastic strains up to 4. 3%. Also in this paper، many important problems including the amount of plastic strain on determining Young’s modulus and Bauschinger effect factor were tested. In this research، to determine the amount of tension- compression yield، the amount of offset has been considered as 0. 01%.