TA2钛合金动态压缩试样中的绝热剪切破坏研究

绝热剪切是金属材料高速变形破坏的重要形式之一，利用分离式霍普金森压杆（SHPB）技术对TA2钛合金的动态力学性能及绝热剪切破坏特性进行研究，实验得到了TA2钛合金动态应力-应变关系。对试样的绝热剪切带形成及发展进行了微观金相观察，结果显示：TA2钛合金动态压缩试样中产生的绝热剪切带呈对称的双圆锥形特征。进一步利用有限元方法对试样动态压缩及变形局域化过程进行了有限元数值分析，模拟结果与实验吻合较好。数值分析结果表明压缩试样表面摩擦对试样中绝热剪切带的形成与破坏特征有着重要影响。

Experimental and Numerical Study of Adiabatic Shear Failure of TA2 Titanium Alloy under Dynamic Compression

Adiabatic shear is known to be a precursor to the failure of metals processed at high strain rate. The present study focuses on the adiabatic shear failure characteristic of TA2 titanium alloy under dynamic compression. The dynamic stress-strain behavior is tested by split Hopkinson pressure bar (SHPB), and adiabatic shear bands (ASBs) are investigated by means of optical microscopy. The metallographic analysis reveals that the ASBs pattern in specimen is symmetrical bi-conical. Furthermore, a comprehensive finite element analysis of shear localization of the deformed cylindrical specimens is carried out. The numerical simulations are in agreement with the experimental results, and the frictional force between the specimen and the Hopkinson bars significantly affects the evolution of shear localization.