【摘要】 平板撞击载荷造成靶样品层裂过程包括孔洞成核，微裂纹生长成宏观裂纹，裂纹切变扩展导致靶局部或完全剥离。本文重点介绍了Ｔａ和Ｔａ－Ｗ合金靶在中低入射应力的平板撞击载荷下裂纹萌生和发展情况，采用金相和扫描电镜观察和分析了Ｔａ和Ｔａ－Ｗ合金靶的原始显微组织和气炮加载试验后回收靶的显微组织变化。研究了靶样品在平板冲击载荷下裂纹萌生和发展同原始晶粒尺寸及靶中Ｗ含量的关系。结果表明，随着合金元素Ｗ的添加及Ｗ含量的增多，裂纹萌生和发展抗力明显降低；在平板撞击加载条件下，减小萌生裂纹长度和增大裂纹切变扩展距离有利于减轻靶样品动态损伤程度，因此，细化靶的原始晶粒尺寸，特别是靶平面方向的晶粒尺寸，可明显提高靶的宏观裂纹萌生和扩展抗力更多还原

【Abstract】 The dynamic fracture of Ta and Ta-W alloys under plate impact loading involves void nucleation, microcrack growth and microcrack propagation, and sample failure by shearing between cracks This paper describes the results of the experimental studies of dynamic crack initiationin Ta and Ta-W alloys under plate impact arising from an air gun In order to investigate the influence of different grain sizes and W contents on crack initiation in the target specimen under the middle impact loading, observations of the microstructure of the recovered targets tested by the air gun have been carried out using optical microscopy and SEM The experimental results indicate that the anti-stress of crack initiation of targets decreases as the W content in the target material increases A material with a fine grain size would be expected to exhibit a higher anti-stress of macrocrack initiation due to the reduction in the dimensions of the microcrack formation and the increment of the inter-microcrack shear distance更多还原