定向凝固水平连铸多晶铜的动态本构方程

A Dynamic Constitutive Equation and It's Application to Unidirectional-Solidified Horizontal-Continuous-Casting Polycrystal Copper

以带有同步组装技术的分离式Hopkinson压杆装置作为热模拟装置,采用基于MTS(MechanicalThresholdStress)模型建立的FCC晶体结构的动态本构方程,确定了定向凝固水平连铸多晶铜动态本构方程参数,研究了其动态冲击特性,获得高温段(685K^1085K)的理论应力-应变曲线与实验曲线相当吻合,而在低温段(低于685K)的理论曲线与实验曲线出入较大。结果也表明定向凝固水平连铸多晶铜在485K和685K之间有一温度能使其回复能达到阀值。

By using MTS （Mechanical Threshold Stress） model and the experimental technique of the split Hopkinson bar with the synchronization assemblage, the dynamic constitutive equation of the unidirectional-solidified horizontal-continuous-casting polycrystal copper was investigated. In the narrow heated furnace designed and manufactured by NPU, the dynamic impact experiments at temperature from 287 K to 1100 K were accomplished. The optimized parameters of the dynamic constitutive equation applying to the unidirectional-solidified horizontal-continuous-casting polycrystal copper were obtained and the theoretical stress-strain curves had a good agreement with experimental curves at temperature from 685 K to 1085 K. The concept of restoration threshold energy was proposed and the parameters of MTS model were also discussed in detail. The results show that only seven parameters in parameters of MTS model are independent and MTS model is not very good to describe the discreteness of mechanical properties, restoration, recrystallization and associated strain softening at temperature from 287 K to 685 K.