Theoretical Modeling of Temperature, Strain Rate and Porosity Dependent Yield Strength of Porous Metallic Material

Yield strength is one of the most crucial mechanical parameters for porous metal materials. A comprehensive study of the influence of temperature, strain rate, and porosity on yield strength is fundamental to ensuring the safety of materials in service. In the present paper, the individual and combined effects of temperature, strain rate, and porosity on yield strength are carefully examined, and then a coupling term, which can effectively and conveniently describe the coupling effect between temperature and strain rate, is introduced. Subsequently, a new theoretical model for the temperature-strain rate-porosity-dependent yield strength of porous metal materials is established. The model is verified by comparing the experimental results with the model predictions, and good agreement is achieved. Particularly, the temperature term in the model is derived solely from physical meanings and does not involve any fitting parameters. The model requires only a few easily obtainable parameters, and it is applicable over a wide range of temperatures, strain rates, and porosities.