Flow characterization of macroporous W-4.8 vol. %ZrO2 alloy during hot deformation with improved constitutive equation and processing maps

In this work, isothermal compression experiments of macroporous W-4.8 vol.%ZrO2 (W-4.8ZrO(2)) at 1300-1600 degrees C and strain rate of 0.005-1 s(-1) were carried out on a Gleeble-1500D thermo-mechanical simulator. The dynamic recovery of W-4.8ZrO(2) is the main "softening" mechanism. On the basis of Arrhenius model, the initial constitutive equation is established by exploring the influence of temperature, strain rate and rheological stress. Based on Arrhenius model, the relationship between flow stress, strain rate and deformation temperature is established. Considering the influence of strain, the improved constitutive equation and the law of material constant changing with the strain are obtained. After that, the hot processing maps were drawn on the basis of the dynamic material model, which is used to analyze the instability mechanism of the W-4.8ZrO(2), and determine the appropriate hot working process parameters (temperature: 1350-1450 degrees C, strain rate: 0.1-1 s(-1)).