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

Abstract

The stress-strain behavior of cast 319-T6 aluminum-copper alloys with three different secondary dendrite arm spacings (SDASs) was studied at high temperatures and under thermomechanical deformation, exposing marked cyclic softening. A two state-variable unified inelastic constitutive model proposed earlier was modified to describe the stress-strain responses of these alloys by considering the variation of hardening and recovery functions of back-stress and drag stress. The SDAS was incorporated in the model as a length-scale parameter, and the material constants were determined systematically from experiments on a cast 319-T6 aluminum with small and large SDASs. The capabilities of the constitutive model were checked by the comparisons of simulations to experiments in the small-strain regime (Ͻ0.005). The results show that the model provides successful simulations for material response after thermal exposure at high temperature and cyclic transient stress-strain behavior. The causes of mechanical behaviors at the macro scale are discussed based on microstructural changes during thermal exposure.

Automotive cylinder heads: recent advances on Thermal-Mechanical Fatigue design and upcoming challenges

“…The A356 alloy is widely used and strengthened by precipitation (T7 heat treatment). Alloys containing copper are also widely used in the automotive industry like the A319 alloy [2]. Many cylinder heads are nowadays produced by die casting.…”

Numerical Simulation and Experimental Validation of Residual Stresses in Water-Quenched Aluminum Alloy Castings

“…During quenching, the part shrinks because of the temperature drop. The nonuniform thermal shrinkage of the part is constrained by the geometric structure and material properties that vary with temperatures and strain rates ( Ref 2,[11][12][13]. Thus, an accurate representation of the material behavior at different temperatures and strain rates is extremely important to the simulation results.…”

Assessment of Thermo-Mechanical Fatigue Behaviors of Cast Al-Si Alloys by Experiments and Multi-Step Numerical Simulation

“…Both inhomogeneous strain distribution induced by the dual phase structure and microscopic damage behavior of the silicon particles should be considered to fully understand the resultant macroscopic thermo-mechanical fatigue resistance. Nevertheless, only a limited number of efforts are available in the current literature in which the authors are devoted to obtaining the effects of various factors on the macroscopic thermo-mechanical fatigue resistance; such as SDAS, 1,2) porosity, 2,3) chemical composition, 2) heat treatment 2,3) and applied thermo-mechanical conditions. 5) It has been clarified in terms of thermal stress hysteresis and fatigue lives that the thermo-mechanical fatigue resistance is improved with the decrease in porosity 2,4) and silicon modification.…”

“…1,2) It has been demonstrated that phenomenological constitutive modeling was applicable to simulate the thermomechanical responses of the cast aluminum alloys initially with time-independent 6) and later with time-dependent assumptions.…”