Modeling high-temperature stress-strain behavior of cast aluminum alloys

Abstract

A modified two-state-variable unified constitutive model is presented to model the high-temperature stress-strain behavior of a 319 cast aluminum alloy with a T7 heat treatment. A systematic method is outlined, with which one can determine the material parameters used in the experimentally based model. The microstructural processes affecting the material behavior were identified using transmission electron microscopy and were consequently correlated to the model parameters. The stress-strain behavior was found to be dominated by the decomposition of the metastable ' precipitates within the dendrites and the subsequent coarsening of the phase, which was manifested through remarkable softening with cycling and time. The model was found to accurately simulate experimental stressstrain behavior such as strain-rate sensitivity, cyclic softening, aging effects, transient material behavior, and stress relaxation, in addition to capturing the main deformation mechanisms and microstructural changes as a function of temperature and inelastic strain rate.

Effect of Frequency, Environment, and Temperature on Fatigue Behavior of E319 Cast Aluminum Alloy: Stress-Controlled Fatigue Life Response

“…At a given stress level, integration of the crack growth relation in Eqs. [2] and [4] provides the fatigue propagation life, which is equivalent to the total fatigue life for pore-containing alloys. As such, S-N behavior in environments with different water exposure can be predicted ( Figure 9).…”

“…By substituting the corresponding dynamic Young's modulus and yield strength at each temperature, the S-N behavior at elevated temperature can also be predicted based on integration of Eqs. [2] and [4], as shown in Figure 10. This method predicts the S-N curve at elevated temperature based on the crack growth data at room temperature and the dependence of Young's modulus and yield strength on temperature.…”

“…The frequency effect on S-N behavior at elevated temperature can be predicted based on integration of Eqs. [2] and [4], as long as the Young's modulus and yield strength at a given temperature are known. Figure 11 presents the predicted S-N curves at 20 kHz and 75 Hz at 150°C and 250°C, respectively.…”

“…[2] It is important to examine the influence of temperature on fatigue performance of E319 cast aluminum alloy. In addition, the potential effects of frequency on fatigue behavior of E319 aluminum alloy at elevated temperature need to be investigated when extending the application of ultrasonic fatigue technique to elevated temperature condition.…”

Stress-strain response of a cast 319-T6 aluminum under thermomechanical loading

“…model as proposed here to predict stress-strain response under complex loading conditions. [27] 5. The proposed model is capable of simulating the transition from the initial to final drag stress as a function of The unified model provided a successful simulation for cyclic stress-strain curves, material behavior after thermal temperature and time.…”