In many applications—such as machining, metal forming, high-velocity impacts, or high-energy deposition of metals—materials experience deformation at very high strain rates. These conditions often result in self-heating to elevated temperatures due to adiabatic processes. In such cases, the stress-strain response represents a balance between hardening effects (from strain and strain rate) and thermal softening.

Additionally, the ambient temperature can differ significantly from room temperature, altering the mechanical response of the material and the strain-rate effects. At high temperatures, materials typically become more ductile, whereas at low temperatures, material strength often increases, and the behavior shifts from ductile to brittle.

Under these conditions, it is essential to define accurate material models to achieve reliable numerical predictions. This, in turn, requires the development of methodologies and experimental setups to thoroughly investigate the mechanical response of materials. Since temperature and strain-rate sensitivities are interdependent, thermal effects observed in quasi-static tests cannot always predict material behavior under dynamic loading.

To account for the coupled effects of temperature and strain rate, material models must incorporate the thermal component of stress. Moreover, it is critical to establish robust testing methodologies that comprehensively explore the entire range of temperature and strain-rate fields relevant to the application.