Effect of cooling process on the formation of duplex microstructure in Zr–2.3Nb alloy
Effect of cooling process on the formation of duplex microstructure in Zr–2.3Nb alloy
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DOI：
10.1016/j.jallcom.2015.08.105
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发表时间：
2015-12
影响因子：
6.2
通讯作者：
Ming Zhang;Fucheng Zhang;Zhi-nan Yang;Yingnan Li;Lin Qu;Huijuan Zhen
中科院分区：
文献类型：
--
作者：
Ming Zhang;Fucheng Zhang;Zhi-nan Yang;Yingnan Li;Lin Qu;Huijuan Zhen
冷却过程对Zr-Nb合金双相组织的形成有重要影响。为了进一步了解其对显微组织的影响，对退火试样进行了炉冷、空冷和水冷三种冷却方式。结果表明，空冷和水冷试样的相变机制和相组成不同，但空冷和水冷试样均能获得等轴晶组织和复相组织。空冷工艺的双相组织由扩散型转变形成，由初生α相、次生α相、ω相和残余β相组成;水冷工艺的双相组织由置换型转变形成，由初生α相、α′相和ω相组成。在相变过程中，由于显微应变的影响，α′相内存在大量位错。随着冷却速度的增加，强度增加，延伸率下降。然而，空冷和水冷试样具有较高的强度和延伸率的乘积值，揭示了两种双重组织的高安全性，尽管它们的差异。
The cooling process is important for the formation of duplex microstructure in Zr–Nb alloy. To further understand its effect on the microstructure, three cooling methods, furnace cooling, air cooling and water cooling, were carried out on the annealed specimens. The results show that the equiaxed microstructure can be obtained in furnace-cooled specimens with equiaxed α grains and residual β phase, and the duplex microstructure can be obtained via the air cooling and water cooling processes, in spite of the different transformation mechanisms and phase constitutions. The duplex microstructure for the air cooling process was formed via diffusion-type transformation and consisted of primary α phase, secondary α phase, ω phase and the residual β phase, while for the water cooling process it was formed via displacive-type transformation and consisted of primary α phase, α′ phase and ω phase. There were many dislocations within the α′ phase for the microstrain during the phase transformation. The strength increased and elongation decreased with increasing cooling rate. However, the air- and water-cooled specimens possessed a high value of product of strength and elongation, revealing a high security for the two duplex microstructures, in spite of their differences.