纯钒在冲击加载下的动态拉伸断裂和弹性波衰减特性

利用平板撞击和激光干涉测速技术，实验研究了国产热等静压纯钒在压力5.2~9.0 GPa、拉伸应变率0.47×10⁵~1.19×10⁵ s^-1冲击加载下的层裂特性。结果表明：国产热等静压纯钒具有较强的抗动态拉伸断裂能力，其层裂强度在4.0~5.3 GPa范围，明显高于相似加载条件下文献给出的熔炼钒结果，这主要与热等静压加工工艺下纯钒杂质含量更低、内缺陷更少有关；同时，纯钒层裂强度对冲击压力和拉伸应变率均比较敏感。此外，对弹塑性加载速度剖面的分析发现：在6 mm样品厚度范围，纯钒的弹性波幅值随样品厚度增大而减小，雨贡纽弹性极限随样品厚度的衰减规律较好地满足指数关系σ_HEL=3.246（h_s/h₀）^-0.386，h₀为单位长度。

Dynamic tensile fracture and the decay of elastic precursor wave in shocked pure vanadium

By using plate impact and velocity interferometry, the dynamic tensile fracture (spall) of shocked pure vanadium was studied in the pressure range of 5.2-9.0 GPa, where the average tensile strain rate was in the range of 0.47×105-1.19×105 s-1. All the vanadium samples used here were made by the hot isostatic pressing (HIP) method. Our results show that the HIP vanadium has a higher spall strength than those given in literatures, which lies in the range of 4.0-5.3 GPa, and increases with both the shock pressure and tensile strain rate. The higher spall strength of the HIP vanadium can be ascribed to the higher purity and fewer initial defects in material than those made by the remelting method. Additionally, the analysis on elastic precursor wave in vanadium indicates a power decay of Hugoniot elastic limit (σ_HEL) with the dimensionless thickness of the sample (h_s/h₀), where h₀ is a unit length. The coefficient and exponent of the power function best fitting the experimental data are 3.246 and -0.386, respectively, when the vanadium sample's thickness h_s is no greater than 6 mm.