装甲板弹坑底部冠状裂纹的观测与分析

发射小口径杆式穿甲弹对30CrMnMo装甲钢板进行穿甲侵彻嵌入试验，并.对靶板弹坑剖面进行扫描电镜观测及能谱分析。装甲板弹孔底部剖面除了产生绝热剪切带外，还观测到弹坑底部下面深1?2mm处形成一条或几条冠状裂纹。无论穿甲弹芯是钨合金还是钨纤维复合材料，弹坑底部均产生冠状裂纹。侵彻过程中，弹体破坏变形局部化和弹芯头部材料不断销蚀，造成弹、靶接触区域局部瞬间不均匀卸载，卸载波相互作用可形成局部围绕弹坑底部的冠状裂纹。冠状裂纹与绝热剪切带在局部区域交汇，构成穿甲侵彻过程中装甲钢板破坏的前期模式。

Observation and Analysis of Coronary Cracks Beneath the Crater in Armor-plate

Embedding tests of 30CrMnMo armor-plate were performed by fired small-caliber rod armor piercing projectile, and microstructures of the section of crater were investigated with scanning electron microscope and X-ray diffraction. The results show that besides formed adiabatic shear bands near the crater, coronary cracks are also found distinctly at t-he location of 1～2 mm beneath the crater. Coro-nary cracks beneath the crater are all generated, whether the armor piercing core is tungsten heavy al-loy or tungsten fiber reinforced composite. In the process of penetration, the parts between the crater bottom and the coronary cracks are first broken and consumed, second the new coronary cracks near the crater can be produced again. It reveals that the crater in armor-plate is extended deeply by layer and layer. The reason of producing coronary cracks is that the materials are suddenly unloaded by bro-ken fragment, which can cause the interaction of release stress waves. The tested result also indicates that adiabatic shear bands and coronary cracks can be joined at near crater to result in the initial dam-age in armor-plate.