Mechanical behaviour and microstructural characterizations of ultrafine grained Zircaloy-2 processed by cryorolling
Mechanical behaviour and microstructural characterizations of ultrafine grained Zircaloy-2 processed by cryorolling
复制标题
DOI：
10.1016/j.msea.2014.02.025
复制
发表时间：
2014-05
期刊：
影响因子：
6.4
通讯作者：
Sunkulp Goel;N. Keskar;R. Jayaganthan;I. Singh;D. Srivastava;G. K. Dey;N. Saibaba
中科院分区：
文献类型：
--
作者：
Sunkulp Goel;N. Keskar;R. Jayaganthan;I. Singh;D. Srivastava;G. K. Dey;N. Saibaba
本工作研究了低温轧制 (CR) 加工的超细晶 Zircloy-2 的机械性能和微观结构特征。固溶的 Zircloy-2 在液氮温度 (77 K) 下进行轧制，厚度减少量不同 (25–85%)。由于动态回复的抑制，冷冻轧制的 Zircloy-2 中的位错密度<ρ>随着真实应变的增加而增加。 CR Zircloy-2 的 EBSD 分析揭示了初始应变硬化，这是由于在样品变形高达 50% 应变期间 {10 1´ 2}< 1´ 011> 拉伸和 {11 2´ 2}< 1´ 1´ 23> 压缩孪晶的激活而发生的。在随后的变形过程中，棱柱滑移和基底滑移被激活。小角度晶界的比例随着真实应变的增加而增加，厚度减少最多 50%，但对于 CR85% 合金，大角度晶界的比例有所增加。 CR 85% 合金的硬度和屈服强度值分别为 282 HV 和 891 MPa。与 CR 85% 合金相比，退火后的 CR 85% 合金表现出更高的延展性（轧制方向和横向方向分别为 9.5% 和 11.2%）。退火后的Zircaloy-2 显示出由超细晶粒和纳米晶粒组成的异质微观结构。
The mechanical properties and microstructural characteristics of ultrafine grained Zircaloy-2 processed by cryorolling (CR) were investigated in the present work. The solutionised Zircaloy-2 was rolled at liquid nitrogen temperature (77 K) with different thickness reductions (25–85%). The dislocation density< ρ> in the cryorolled Zircaloy-2 increases with increasing true strain due to the suppression of dynamic recovery. EBSD analysis of CR Zircaloy-2 revealed initial strain hardening, which has occurred due to activation of {10 1¯ 2}< 1¯ 011> tensile and {11 2¯ 2}< 1¯ 1¯ 23> compressive twins during deformation of samples up to 50% strain. The prismatic and basal slips were activated during subsequent deformation. The fraction of low angle boundaries has increased with increasing true strain up to 50% thickness reduction but the fraction of high angle grain boundaries has increased for CR85% alloy. The CR 85% alloy showed hardness and yield strength values of 282 HV and 891 MPa, respectively. The annealed CR 85% alloy showed higher ductility (9.5% and 11.2% in rolling and transverse direction, respectively) as compared to CR 85% alloy. The annealed Zircaloy-2 showed heterogeneous microstructure consisting of ultrafine grains and nanograins.