Development of Several Constitutive Models to Predict Flow Stress of Biomedical Grade Co–28Cr–6Mo Alloy during Thermo-Mechanical Processing
摘要
The true stress-true strain curves of a biomedical grade Co–28Cr–6Mo alloy were obtained through isothermal uniaxial compression tests on a Gleeble-3800 thermo-mechanical simulator. Based on the experimental data, the modified Johnson–Cook model, strain compensated Arrhenius-type model and microstructure-based constitutive model were constructed in a wide range of temperatures (900–1200°C) and strain rates (0.001–10 s–1). The prediction accuracy of the developed constitutive models was estimated by the determination coefficient and the average absolute relative error between experimental and predicted flow stress values. These values are 0.9857 and 7.8% for the modified Johnson-Cook model, 0.9504 and 13.01% for the strain compensated Arrhenius-type model, and 0.9948 and 2.45% for the microstructure-based constitutive model, respectively. The result clearly demonstrates that the microstructure-based constitutive model is able to describe the hot flow stress behavior more correctly, compared to the other proposed constitutive models.