Constitutive modelling of a tungsten heavy metal alloy

Abstract
The dynamic mechanical behaviour of a tungsten heavy metal alloy (WHA) with potential use as a kinetic energy penetrator is investigated. Mechanical properties related to tensile loading are measured at strain rates up to 400 s ^-1 and at temperatures from 20 C to about 500 C. From the experimental data parameters for the constitutive equations developed by Johnson and Cook (J&C) as well as Zerilli and Armstrong (Z&A) are determined. From the extracted models isothermal and adiabatic flow stress curves are calculated and compared to experiments. At high strain rates or high temperatures the J&C model deviates about 5-10% from experimental results, while the Z&A model shows a better agreement with the collected data. It should be emphasised that the Z&A model used in this work is developed for materials with body centred crystals whereas the WHA is a composite with both face centredand body centred crystals.