Ti-6Al-4V合金两次侵彻弹着点损伤及组织演化

利用装甲钢平头弹丸垂直侵彻Ti-6A1-4V合金靶板,分析相同弹道学条件下,两次侵彻同一靶板不同位置材料的微观组织与弹着点损伤演化特征.研究靶板两次侵彻损伤程度和一次侵彻对再次侵彻造成的影响.结果表明,两次侵彻形成的剪切带都萌发于靶板与受力方向成45°角方位.第1次侵彻形成的剪切带较短,剪切带有弯折与扭转,剪切带在与受力方向成45°角萌发后沿浅表面向30°角方向扩展.第2次侵彻形成的剪切带较长,剪切带内孔洞相连,剪切带在与受力方向成45°角方位形成后向平行于受力方向纵深发展.第2次剪切损伤大于第1次剪切损伤的主要原因是第1次侵彻过程中靶板局部区域形成了绝热剪切带,从而引起了靶板材料强度增高、残余应力呈不均匀分布以及笫2次侵彻过程中残余应力与应力叠加、局部应变硬化以及应变率硬化所致.

Damage Behavior of Craters and Microstructure Evolution in Ti-6Al-4V Alloy by Twice Penetration

The target of Ti-6Al-4V alloy was impacted vertically by an armored steel plane bullet. The damage behavior of craters and microstructure evolution in twice penetration under the same ballistics condition were analyzed. The results show that the adiabatic shear bands formed in twice penetration come into being at 45o direction along with stress. The shear bands occurring in the first penetration are petty with winding and warping, and expand from 45o to 30o along with the shallow surface. Nevertheless, the shear bands occurring in the second penetration are longer with a large number of apertures and cavities, and expand from 45o to parallel with the shocking-loading direction. Results indicate that the heavier shear damage of the second impact than that of the first impact is owing to the formation of the shear bands in the first penetration, which could cause the increasing of strength of target material and the heterogeneity of the residual stress as well as the residual stress, the stress superposition, local strain hardening and strain rate hardening caused by the second penetration