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介绍了中国科学技术大学在钨合金和钛合金的绝热剪切变形和破坏研究方面的工作。对截头圆锥形和预扭斜切圆柱形钨舍金试件进行了分离式Hopkinson压杆试验,通过微观观察和数值模拟分析了试件中剪切失稳和绝热剪切带形成的机理,发现鸽合金的细观结构和试件的应力状态对绝热剪切带形成的敏感性和位置有重要影响.通过钛合金板的冲塞实验研究了绝热剪切和动态破坏的联系,发现由于沿剪切带的孔洞形核和合并过程而出现断裂,最后导致冲塞.所有这些情况下,绝热剪切带在裂纹形成和扩展中起支配作用,正是绝热剪切带造成了试件的动态断裂.
The work of the University of Science and Technology of China on adiabatic shear deformation and failure of tungsten alloys and titanium alloys is introduced. A separate Hopkinson pressure bar test was carried out on a truncated conical and pre-skew cylindrical tungsten-sheathed specimen. The mechanism of shear instability and adiabatic shear band formation in the specimen was analyzed by microscopic observation and numerical simulation. It is found that the mesostructure of the pigeon alloy and the stress state of the specimen have an important influence on the sensitivity and position of the adiabatic shear band.By the impulse test of the titanium alloy plate, the connection between adiabatic shear and dynamic failure is found, Shear fracture occurs in the nucleation and consolidation process of the shear band and eventually leads to plugging.In all these cases, the adiabatic shear band plays a dominant role in crack formation and propagation, which is caused by the adiabatic shear band fracture.