Abstract

To establish constitutive equations for the implementation of load determination and numerical simulation, a new Mg-2.70Zn-1.34Y-0.37Ca-0.02Zr magnesium alloy has been fabricated by multidirectional forging and hot rolling, and its true stress-true strain curves were obtained at elevated temperatures and different strain rates. The flow stress curves at 723K and lower strain rates exhibit a slow strain hardening stage, followed by a strain softening stage. Except for this, other flow stress curves behave like conventional single peak curves. An Arrhenius constitutive equation was established. The determination coefficient was 0.978, the ratio of predicted stress to experimental stress was 0.961, and the average absolute relative error was 2.1%, indicative of high accuracy of the hyperbolic sine law. A modified Fields- Backofen constitutive equation was established. The determination coefficient was 0.924, and the ratio of prediction stress to experimental stress was 0.987, indicative of high prediction precision..

Keywords: Mg-Zn-Y alloy; Multidirectional forging; Rolling; Hot tension; Flow stress; Constitutive equation