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通过Taylor杆冲击实验(撞击速度范围为145-306m/s)研究Ti-6Al-4V合金在高应变率加载条件下的动态断裂行为。研究表明:该合金的临界破碎速度为217-236m/s;当撞击速度增大至260m/s时,试样断口表面除平面区及韧窝区外,还存在明显的熔化区域,试样头部端面裂纹分布呈现出自组织特征;试样撞击端面具有圆弧状头部的特殊裂纹,且未在裂纹前端发现变形组织及绝热剪切带;这类特殊的裂纹也是由于绝热剪切带而形成的,沿两最大剪应力方向形核、扩展,并最终相交形成三维“交错屋脊”状结构。
The dynamic fracture behavior of Ti-6Al-4V alloy under high strain rate loading conditions was studied by means of Taylor rod impact test (impact velocity range 145-306 m / s). The results show that the critical breaking speed of the alloy is 217-236m / s. When the impact velocity increases to 260m / s, the surface of the fracture surface is obviously melted except for the flat area and the dimple area. The crack distribution in the end face presents self-organization characteristics. The specimen has special arc-shaped head cracks on the end face and no deformation structure and adiabatic shear band are found at the front of the crack. These special cracks are also formed by the adiabatic shear band , Nucleate and extend along the two directions of maximum shear stress, and eventually intersect to form a three-dimensional “staggered ridge” structure.