Dynamic Softening Mechanism and an Improved Unified Constitutive Model for an Al–Cu–Mn–Fe–Zr Alloy during Warm Deformation

Abstract

Deformation behavior of an Al–Cu–Mn–Fe–Zr alloy is investigated by plane strain compression tests at a warm deformation region. The flow stress first increases and then keeps steady, and the flow stress increases with reducing temperature or raising strain rate. However, the influence of strain rate on flow stress is weak at 100 and 150 °C. The dynamic recovery (DRV) mechanism is the dominant mechanism to balance the work hardening, and a larger number of dislocations are consumed at low strain rates. So, the deformed grains are difficult to reach the critical strain for dynamic recrystallization (DRX). When the strain rate is relatively high, the critical strain can be reached in a short time, which promotes the process of DRX. In addition, an improved unified constitutive model is built based on the evolution of dislocation density. The predicted flow stresses are in a close agreement with the measured results, proving that the built model can nicely reproduce the flow behavior.

Prediction of Flow Stress and Characterizing the Deformation Mechanism of As‐Extruded 7005 Aluminum Alloy

“…This is attributed to the weakening of WH at high temperatures and the strengthening of DRV. [ 36 ] Under low‐temperature conditions (temperature < 673 K) and strain rates greater than 0.1 s −1 , in the latter stages of deformation (after a strain of 0.6), the stress increased with increasing strain, which may be attributed to dynamic strain aging (DSA). [ 37 ] This phenomenon could result from the interaction between solute atoms and moving dislocations.…”

“…Consequently, dynamic softening caused by DRV becomes more prominent, leading to a decrease in flow stress with a decreasing strain rate. [ 36 ] In the hot deformation process of the as‐extruded 7005 Al alloy, DRV is the primary mechanism that balances WH.…”

Hot Deformation Analysis and Microstructure Evolution of a Novel Al–Cu–Li Alloy by Isothermal Compression

“…The difference in the peak stress is also because an increase in temperature promotes dynamic softening, which reduces the peak stress. [ 22 ] Meanwhile, an increase in strain rate promotes work hardening, which increases the peak stress. Furthermore, the alternation of pinning effects and dislocation depinning in the alloy results in serrated flow characteristics, [ 23 ] as shown in Figure 2b,c.…”

Forming Quality and Microstructure Evolution of AA6061‐T6 Aluminum Alloy Joint during Flow Drill Screwing Process

“…Under the influence of the high‐strain‐rate deformation caused by the high‐speed rotation of the screw, the alloy in this region undergoes severe shear deformation. The accumulated thermal energy enhances the obvious grain refinement, and the continuous DRX (CDRX) leads to the formation of a fine‐grained zone, [ 33,34 ] as shown in Figure 5d. The morphology and volume of the strengthening phase in the aluminum alloy are greatly affected by strain rate and temperature.…”