Development of equations for strain rate sensitivity of UFG aluminum as a function of strain rate

摘要: Abstract Strain rate sensitivity ( m -value) of ultrafine grain (UFG) AA 1050 and 5052 sheets processed by accumulative roll-bonding is investigated versus strain stress relaxation (SR) test at ambient temperature. The results show a weak viscous nature deformation for specimens as compared to ones. So that much less negligible are obtained this material due dislocation boundary mobility limitation caused Mg solute atoms. In order formulate UFG aluminum function rate, three phenomenological two empirical models developed assessed the experimental results. It shown since thermally activated glide not single governing phenomenon, model based on mechanism fails predict variation -value rate. Contribution sliding (GBS) can result in fitted lower rates, yet suitable higher rates. However, third which annihilation was taken into account besides mentioned phenomena well trend full range Since parametric formulated independent variable time with no analytical solution, equations presented more simple straightforward models. these give useful formulas estimation extrapolation relatively high rates common processes where monotonic expected.