应变水平对锆合金动载下塑性变形机制的影响

发布时间：2018-05-26 18:47

本文选题：锆合金 + 应变　；参考：《稀有金属材料与工程》2017年06期

【摘要】：基于实验设计研究了应变参数对锆合金动载下塑性变形机制的影响。通过控制应变速率,采用应变限位环的方法实现了锆合金高应变速率下应变参数的单一分离,应变速率为2300 s~(-1)时,获得了4个不同的应变水平:0.11、0.21、0.30、0.33。基于锆合金高应变速率不同应变下微观组织的表征,预测了应变参数对锆合金动载下塑性变形过程的影响。结果表明:形变带和转变带是锆合金不同应变阶段塑性变形的重要方式,形变带内部由严重变形的晶粒组成,而转变带内部主要由100~300 nm的细小等轴晶粒组成。在变形初始阶段,锆合金变形以柱面滑移和锥面滑移为主,以孪生为辅;随着应变的增加,位错持续增殖,位错的塞积导致应力增加,直至最大抗压强度;当应变达到一个临界值时,形成形变带;随应变继续增加,形变带发生动态再结晶,演化为转变带;应变继续增加,便会在剪切带内部诱发微空洞、微裂纹,直至材料断裂。
[Abstract]:Based on the experimental design, the effect of strain parameters on the plastic deformation mechanism of zirconium alloy under dynamic loading was studied. By controlling strain rate, single separation of strain parameters at high strain rate of zirconium alloy was realized by using strain limit ring method. At strain rate of 2300 s-1, four different strain levels: 0.110.21n0.300.30g 0.33 were obtained. Based on the characterization of microstructure of zirconium alloy at high strain rate, the influence of strain parameters on the plastic deformation process of zirconium alloy under dynamic loading was predicted. The results show that the deformation band and the transition band are important for the plastic deformation of zirconium alloy at different strain stages. The deformation band is composed of severely deformed grains, while the inner transformation band is mainly composed of 100 ~ 300nm fine equiaxed grains. In the initial stage of deformation, the deformation of zirconium alloy is dominated by cylinder slip and cone slip, supplemented by twinning, and the dislocation continues to proliferate with the increase of strain, and the piling of dislocation leads to the increase of stress until the maximum compressive strength is reached. When the strain reaches a critical value, a deformation band is formed; with the increase of strain, dynamic recrystallization occurs in the deformation band, which evolves into a transition zone; if the strain continues to increase, microvoids and microcracks will be induced in the shear band until the material breaks.
【作者单位】：表面物理与化学重点实验室;中国工程物理研究院;
【基金】：国家自然科学基金(51401187)
【分类号】：TG146.414

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