Abstract As a model bcc metal, tantalum and its alloys have wide applications in defense-related fields. The KHL (Khan, Huang, Liang, 1999) model and the constitutive model proposed by Nemat-Nasser et al (Nemat-Nasser and Kapoor, 2001) for tantalum and its alloys were analyzed and compared with each other. A set of published data recorded during elastic-plastic deformations of tantalum, tantalum alloy containing tungsten of 2.5% (Ta-2. 5W), over a wide range of strains, strain rates, and temperatures were used to correlate the two models. Overall, it can be concluded that KHL model correlates much better with the data than the model used by Nemat-Nasser et al.