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

This study explores isothermal hot compression of the as‐extruded 7005 aluminum alloy within a temperature range of 573–823 K, with strain rates from 0.001 to 1 s−1 and a strain of 1.2. Three constitutive equations, employing hyperbolic sine, power law, and exponential functions, were formulated and compared to predict rheological peak stress accuracy and applicability. The results indicate that the hyperbolic sine function is suitable across all stress levels, the power law function for low stress (< 56 MPa), and the exponential function for high stress (> 56 MPa). Introducing a strain compensation function enhances hyperbolic sine function accuracy. The stress exponent (n) and activation energy (Q) decrease with increased deformation, indicating a transition in the deformation mechanism from early‐stage dislocation climb to later‐stage dislocation glide. At 773 K with strain > 0.6, the presence of precipitates maintains the n value at approximately 4. Solute atoms (Zn, Mg, and Zr) and precipitates (MgZn2 and Al3Zr) impede diffusion and dislocation motion, resulting in deformation activation energies surpassing pure aluminum. Additionally, kernel average misorientation maps demonstrate that higher deformation temperatures and lower strain rates reduce internal residual stresses.This article is protected by copyright. All rights reserved.

Section: Resultsmentioning

confidence: 99%

“…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.…”

Section: Resultsmentioning

confidence: 99%

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

Lin,

Tzeng

2024

“…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.…”

Section: Resultsmentioning

confidence: 99%

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

Chen

et al. 2023

“…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.…”

Section: Results and Analysismentioning

confidence: 99%

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

Huang

Shan³

et al. 2023

Flow drill screwing (FDS) is the optimal process to realize the single‐side connection of metal sheets. However, the plastic deformation and high fractional temperature during the plate connection process significantly impact the mechanical properties and microstructure of the metal sheets. Herein, the AA6061‐T6 sheet is connected by the FDS process, and the forming quality and microstructure evolution of the alloy are studied. The results show that the plate and the screw are mechanically connected. Obvious plastic deformation and recrystallization occur in the aluminum alloy around the screw, resulting in a fine‐grained zone near the joint interface. The recrystallization phenomenon in the central bushing region promotes the intermolecular fusion between the plates. The high temperature in the connection process partially promotes the dissolution of the strengthening phase, resulting in a decreased strength of the alloy matrix near the screw. The softening zone and hardening zone appear in the plates after the connection, and the hardness values are 55.8% and 105.7% of the alloy matrix.