纯钽动态本构关系的实验研究

An experimental study on the dynamic constitutive relation of tantalum

利用材料试验机和分离式霍布金森压杆实验装置测量了纯钽在较宽温度(-100～550℃)和应变率(10-5～103s-1)范围内的应力 应变曲线,该曲线表明钽的流动应力对温度和应变率都很敏感。利用所测得的应力 应变曲线拟合了钽在不同应变率和不同温度下的Johnson Cook与Zerilli Armstrong本构方程,Zeril li Armstrong本构方程与实验数据基本吻合,Johnson Cook本构方程与实验数据吻合得不太好。对Johnson Cook本构方程中的应变率强化项作了修正,修正后的Johnson Cook本构方程与实验数据吻合比修正前的好。

The stressstrain curves of pure tantalum under a wide temperature range(-100～550℃) and a strainrate range(10-5～103 s-1) have been measured with a material testing system and a splitHopkinson pressure bar system.The results show that the flow stress of tantalum is sensitive to both temperatures and strainrates.JohnsonCook and ZerilliArmstrong constitutive functions were fitted out respectively on the basis of the experimental data.The fitting is better for ZerilliArmstrong constitutive functions.Also a good fitting to JohnsonCook constitutive function is achieved after the strainrate hardening term in them is modified.