Thermomechanical behavior and constitutive modeling of tungsten-based composite over wide temperature and strain rate ranges

Thermomechanical behavior of tungsten-based composite 93 W-4.9Ni-2.1Fe is investigated systematically over strain rates ranging from 0.001 to 3000 s ^-1, and temperatures ranging from 173 to 873 K. Different micromechanisms are found in the evolution of microstructures between quasi-static and dynamic tests. The deformation of the tungsten particles is sensitive not only to strain rates, but also to plastic strain levels; the interaction between the grains is found to be the determining factor that cracks the grains, regardless of strain rates. Based on experimental results, two phenomenological and five physically-based constitutive models are established through a procedure of regression analysis and constrained optimization. Descriptive and predictive capabilities of these models are examined and compared. The performance of the models in characterization of work-hardening, temperature, and strain rate effects of the material is also investigated separately.