A study of Johnson-Cook model coefficient corrections in the cryogenic machining of Ti-5AL-2.5Sn alloy

Abstract

The accuracy of constitutive models directly affects the simulation and analytical calculations of material cutting. Currently, most constitutive models primarily focus on the high-temperature dynamic mechanical behavior of materials, while research on low-temperature dynamic mechanical properties is relatively limited. Therefore, this study targets the Ti-5Al-2.5Sn alloy and employs an electronic universal testing machine and a split Hopkinson pressure bar to conduct static and dynamic compression tests within a temperature range of −196 °C to 600 °C. Furthermore, we constructed a Johnson-Cook constitutive model that accounts for low-temperature dynamic performance using the mechanical curves obtained. To validate the accuracy of the model, we selected cryogenic cutting as the application scenario and employed a combination of experimental and simulation methods to verify the newly developed model. The results indicate that as the temperature decreases or the strain rate increases, the material exhibits a significant strengthening effect along with grain refinement. The newly fitted constitutive model addresses the shortcomings of traditional models in adapting to low-temperature mechanical properties. In the validation of cutting forces during cryogenic cutting, the model’s error is controlled within 15%. This research provides theoretical guidance for cryogenic machining processes and the design of low-temperature structures.