Abstract:To understand the characteristics of extruded, forged and annealed tantalum(Ta), the chemical composition, hardness and microstructure of Ta in each working process are measured. Mechanical performance of Ta after each working process was studied. The thermomechanical responses of forged and annealed Ta were investigated at different temperatures and different strain rates, using Instron servohydraulic testing machine and the split Hopkinson compression bar. Results show: (1) elements O and C in as-extruded Ta were 30% higher than those in Ta powder, but element of N was 50% lower than that of powder; (2) as-extruded Ta was forged and annealed at 1523 K for 2 h, complete recrystalization occured. Grain number and hardness of Ta disk changed from center to edge; (3) the mechanical performance in certer of the Ta disk showed remarkably anisotropy, this phenomenon appeared slightly at edge of the disk. Finally, Based on mechanism of thermal activation glide of dislocation, and physical concept of plastic deformation, a constitutive modeling was deduced to predict palstic flow stress of Ta. Modeling results were compared with the results of Johnson-Cook modeling and experimental results. The results show that the present dynamic constitutive modeling can make a satisified predication to the plastic flow seress.