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材料在高速成形过程中其成形性能和成形精度更能够得到显著的提高。但是,材料在高速成形过程中的断裂机制尚不清楚或未知。因此,采用TA3钛合金材料利用Hopkinson压杆实验并结合显微镜、扫描电镜和应力响应分析手段研究了该材料在动态变形过程中的断裂机制。结果表明,绝热剪切带是导致宏观裂纹的形成和扩展以及流动软化的根源;TA3钛合金动态变形微观断裂机制为纺锤状孔洞在绝热剪切带内各自独立形核,然后各自长大从而相互贯通,形成微观裂纹;第二相粒子的偏聚是微观裂纹发生的源泉。
Materials in the high-speed forming process its forming performance and forming precision can be significantly improved. However, the fracture mechanism of the material during high-speed forming is unclear or unknown. Therefore, using TA3 titanium alloy Hopkinson pressure bar experiment and combined with microscopy, scanning electron microscopy and stress response analysis of the material in the dynamic deformation of the fracture mechanism. The results show that the adiabatic shear band is the source of macroscopic crack formation and propagation and flow softening. The micro-fracture mechanism of dynamic deformation of TA3 titanium alloy is that the spindle-shaped holes are independently nucleated in the adiabatic shear band and then grow up to each other Through, the formation of micro-cracks; second phase particles segregation is the source of micro-cracks.