Microstructural characterization and evolution mechanism of adiabatic shear band in a near beta-Ti alloy
Microstructural characterization and evolution mechanism of adiabatic shear band in a near beta-Ti alloy
复制标题
近β-Ti合金的微观结构表征及绝热剪切带演化机制
DOI：
10.1016/j.msea.2010.12.053
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发表时间：
2011-03-15
期刊：
影响因子：
6.4
通讯作者：
Zhang, Q. M.
中科院分区：
文献类型：
--
作者：
Yang, Y.;Jiang, F.;Zhang, Q. M.
利用分离式Hopkinson压杆(SHPB)技术在一种准β钛合金的帽状试件中获得了绝热剪切带(ASB)。用透射电子显微镜研究了ASB的微观结构和相变。结果表明，在剪切带边界观察到了宽度为0.2~0.4微米的细长亚晶，而ASB内部的显微组织由细小的等轴亚晶组成，其尺寸比基体中的亚晶小3个数量级。在ASB中观察到了β-gt；omega((al热))相变，进一步的分析表明，剪切带为omega((al热))相的形成提供了热力学和动力学条件，该合金的高合金化是发生这种转变的另一个重要因素。计算了剪切局部化过程中的热机械历史。用旋转动态再结晶(RDR)机制解释了剪切带内的组织演变机制。动力学计算表明，再结晶细小亚晶是在变形过程中形成的，变形后不会因晶界迁移而发生明显长大。(C)2010爱思唯尔B.V.保留所有权利。
The adiabatic shear band (ASB) was obtained by split Hopkinson pressure bar (SHPB) technique in the hat-shaped specimen of a near beta-Ti alloy. The microstructure and the phase transformation within the ASB were investigated by means of TEM. The results show that the elongated subgrains with the width of 0.2-0.4 mu m have been observed in the shear band boundary, while the microstructure inside the ASB consists of fine equiaxed subgrains that are three orders of magnitude smaller than the grains in the matrix. The beta -> omega((althermal)) phase transformation has been observed in the ASB, and further analysis indicates that the shear band offers thermodynamic and kinetic conditions for the omega((althermal)) phase formation and the high alloying of this alloy is another essential factor for this transformation to take place. The thermo-mechanical history during the shear localization is calculated. The rotational dynamic recrystallization (RDR) mechanism is used to explain the microstructure evolution mechanism in the shear band. Kinetic calculations indicate that the recrystallized fine subgrains are formed during the deformation and do not undergo significant growth by grain boundary migration after deformation. (C) 2010 Elsevier B.V. All rights reserved.