Hot compressive flow stress modeling of homogenized AZ61 Mg alloy using strain-dependent constitutive equations

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 574; pp. 17 - 24
• Main Authors: Wu, Horng-yu, Yang, Jie-chen, Zhu, Feng-jun, Wu, Cheng-tao
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.07.2013; Elsevier
• Subjects: Applied sciences; AZ61 Mg alloy; Constitutive analysis; Constitutive equations; Constitutive relationships; Elasticity. Plasticity; Exact sciences and technology; Flow stress modeling; Magnesium base alloys; Mathematical models; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Strain; Strain rate; Strain-dependent constitutive parameters; Stress-strain relationships; Thermal simulation; AZ61 Mg alloy; Flow stress modeling; Strain-dependent constitutive parameters; Constitutive analysis; Hot deformation; Constitutive equation; Temperature dependence; Experimental data; Plastic flow; Stress strain relation; Theoretical study; Mechanical properties; Compression test; Modeling; Magnesium base alloys; Compressive stress; Hyperbolic equation; Numerical simulation; Diffusion; Power law; Flow stress; Strain rate
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2013.03.005

The experimental stress–strain data from hot compression tests were used to establish constitutive equations in a homogenized cast AZ61 Mg alloy. Hot compression tests were conducted using the Gleeble 3500 thermal simulation machine in the temperature range of 250–450°C and strain rate range of 1×10−3–1s−1. The constitutive analysis was performed based on the effect of strain on the constitutive parameters. Constitutive equations as a function of strain were constructed according to the hyperbolic sine constitutive law. The correlation between the strain-dependent constitutive parameters and flow behavior was analyzed. Results showed that variations in the constitutive parameters with strain were associated with the stress–strain behavior. A comparatively higher scattering was obtained at low strains based on the constitutive equation with the strain-dependent stress multiplier (α) determined by power and exponential laws. However, the constitutive analysis with a constant α determined by the hyperbolic sine constitutive equation showed better estimations between the calculated and experimental flow stresses at different temperatures and strain rate conditions used in this study.