Dynamic expansion crack freezing recovery tests of 6061 aluminum alloy thin-walled cylindrical tubes with different roughnesses after surface processing were carried out with the split Hopkinson pressure bar experimental technique, and the crack initiation, propagation and final fracture mode of the thin-walled metal cylindrical tubes of dynamic expansion fracture process were studied. The results show that:under the same impact pressure, the greater the surface roughness of the thin-walled metal cylindrical tube, the more prone to the expansion of the material in the process of expanding fracture; the crack initiating on the surface of the outer wall is extended from the outside to the inside, and the crack propagation is mainly affected by the stress state at the crack; the fracture mode is dominated by the tensile and shear fracture mechanism, the fracture mode is a mixed type of tension and shear fracture.%采用分离式霍普金森杆实验技术,对表面加工后不同粗糙度的6061铝合金薄壁圆柱管进行动态膨胀断裂冻结回收实验,并对薄壁金属圆柱管动态膨胀断裂过程中裂纹萌生、扩展情况以及最终断裂模式等进行了研究.结果表明:相同冲击压力条件下,薄壁金属圆柱管表面粗糙度越大,材料越容易发生膨胀破裂;裂纹萌生于外壁面,由外向内扩展,并且裂纹的扩展主要受裂纹处应力状态的影响;薄壁金属圆柱管的断裂模式由拉伸和剪切断裂机制起主导作用,其断口为拉剪混合型断口.
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