| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 831223 | Materials & Design (1980-2015) | 2011 | 6 Pages |
In the field of deformation process modeling, the constitutive equations may properly represent the flow behavior of the materials. In fact, these valuable relationships are used as a calculation basis to simulate the materials flow responses. Accordingly, in the present study a hot working constitutive base analysis has been conducted on a 7075 aluminum alloy. This has been performed using the stress–strain data obtained from isothermal hot compression tests at constant strain rates of 0.004, 0.04 and 0.4 s−1 and deformation temperatures of 450, 500, 520, 550 and 580 °C up to a 40% height reduction of the specimen. A set of constitutive equations for 7075 Al alloy have been proposed employing an exponent-type equation. The related material constants (i.e., A, n and α) as well as the activation energy Q for each temperature regime have been determined. The correlation of flow stress to strain rate and temperature can be deduced from the proposed equations. Furthermore, a change in deformation mechanism has been realized in the semi-solid temperature range. This has been related to the onset of lubricated flow mechanism during processing.
► Two constitutive models has been proposed for the hot working of 7075 Al alloy. ► Constitutive models show the temperature and strain rate dependence of flow stress. ► Deformation mechanism changes to lubricated flow at 550 °C during hot deformation. ► Lubricated flow mechanism becomes more pronounced with increasing strain rate.
