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摘要: 利用金相显微镜，对电磁加载下无氧铜（M态TU1）环碎片的颈缩部位进行了金相分析，观察到了颈缩区孔洞长大、汇通及孔洞壁熔化现象。利用球形孔洞模型，分析了颈缩区孔洞长大条件，发现周向偏应力更适合于描述膨胀环颈缩区的孔洞长大。据此，讨论了颈缩区的局域化温升效应。研究结果为延性金属环膨胀颈缩失稳的细观机理研究提供参考。Abstract: The fragmentation tests of high-conductivity oxygen-free copper (M-state TU1) rings have been carried out by the electromagnetically driven expanding ring technique. Using a metallographic microscope, the void growth and coalescence were observed in the necking region of recovery fragment. The void growth conditions in the thin ring were analyzed with a spherical void model. The results showed that the circumferential deviatoric stress is more suitable for describing the void growth in necking zone of the expanding ring. Moreover, the local temperature rise effect of necking region was also discussed. This work may be helpful for the further meso-mechanics studies on necking instability of expanding metal ring.
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