Constitutive equations for elevated temperature flow behavior of commercial purity aluminum

In order to study the high-temperature flow stress of commercial purity aluminum (AA1070), isothermal hot compression tests were conducted at the deformation temperatures varying from 350 to 500 °C and strain rates ranging from 0.005 to 0.5 s−1. The results showed that the flow stress of AA1070 was evidently affected by both the deformation temperature and strain rate. The influence of strain was also incorporated in the constitutive equation by considering the effects of strain on material constants which are consist of β, α, n, A and activation energy Q. The predicted flow stress curves using the proposed constitutive equations well agree with the experimental results of the flow stress for AA1070.

► Strain has significant effect on the flow stress of commercial pure aluminum.
► The hyperbolic law in Arrhenius-type equation gives better estimates between Z and σ.
► The influence of strain in the constitutive analysis has been incorporated.
► The strain effect on the material constants was represented by a fifth order polynomial.
► The developed constitutive equations give a precise estimate for flow stress of AA1070.