加载应力幅值对高纯铜动态损伤演化特性研究

Study on the effect of peak stress on dynamic damage evolution of high pure copper

研究了加载应力幅值对延性金属高纯无氧铜动态损伤演化特性的影响.层裂实验在一级轻气炮上开展,利用不同的飞片击靶速度实现不同加载应力幅值(2.5 GPa,2.75 GPa和3.75 GPa),采用DISAR位移干涉诊断技术测量样品自由面的速度剖面,利用基于白光轴向色差的表面轮廓测试技术测试软回收的样品截面.结果显示:随着加载应力幅值的升高,层裂强度几乎没有变化,但自由面速度剖面上Pull back信号后的回跳速率和幅值显著增大,损伤演化速率显著升高.进一步分析表明:延性金属动态损伤演化过程中微孔洞成核对加载应力幅值单一因素不敏感,但加载应力幅值是微孔洞长大和聚集的主导因素之一.

Effects of peak stress on the properties of dynamic damage evolution of oxygen free high-pure copper （OFHC） are investigated. The spall fracture experiments are conducted in gas gun, and the damage evolution process is studied using the time-resolved free-surface velocity interferometry, also the post-experiment metallurgical analysis of the soft~ recovered samples. It is indicated that, with the increase of peak stress, the spall strength has little changed, but distinct differences are observed in the magnitude and rate of damage at which the velocity rises to the first peak beyond the minima, and the rate of damage evolution increases remarkably. It is concluded that the peak stress is not sensitive to the nucleation of voids, but is one of the most important factors for the growth of voids.