Hot deformation mechanism and microstructure evolution of a new near β titanium alloy
Hot deformation mechanism and microstructure evolution of a new near β titanium alloy
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DOI：
10.1016/j.msea.2013.07.019
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发表时间：
2013-11-01
期刊：
影响因子：
6.4
通讯作者：
Li, J. S.
中科院分区：
文献类型：
--
作者：
Fan, J. K.;Kou, H. C.;Li, J. S.
利用透射电镜（TEM）和电子背散射衍射（EBSD）研究了新型近β钛合金Ti-7333在770 ~ 970 ℃、0.001 ~ 10 s（-1）的热压缩变形条件下的显微组织和变形机制。结果表明，变形参数对组织演变有显著影响。提高温度和降低应变速率均有利于动态再结晶过程的进行。其机制主要是动态回复、球化和动态再结晶。在较高温度和较低应变速率下变形，α相的球化趋势更明显。反之，温度越低，应变速率越高，越有利于α相的细化.随着变形温度的升高和应变速率的降低，变形组织中的小角度晶界所占比例逐渐减少。这说明在变形过程中，小角度晶界将转变为大角度晶界。通过回归分析，得到了再结晶晶粒尺寸D-r与参数Z的关系式：In D-r=8.79964-0.33663ln Z。所有变形样品均呈现出强纤维织构< 001 >和弱< 111 >纤维织构。随着温度的升高和应变速率的降低，< 001 >织构逐渐增强，< 111 >织构逐渐减弱直至消失。(C)2013爱思唯尔有限公司版权所有。
Transmission Electron Microscope (TEM) and Electron Backscattered Diffraction (EBSD) are employed to explore the influence of deformation conditions on microstructure and the deformation mechanism of a new near beta titanium alloy Ti-7333 after hot compression tests which at temperatures ranging from 770 to 970 degrees C and strain rates ranging from 0.001 to 10 s(-1). The results showed that the effect of deformation parameters on microstructure evolution is significantly. Both increasing the temperature and decreasing the strain rate seem to promote the dynamic recrystallization process. The mechanism is dominated by dynamic recovery, globularization and dynamic recrystallization. The globularization trend of a phase is more remarkable deformed at higher temperature and lower strain rate. And reverse, the lower temperature and higher strain rate are more favorable to a phase refinement. The fraction of low-angle grain boundaries in the deformation microstructure decreases with the increasing of temperature and decreasing of strain rate. It illustrates the low-angle grain boundaries would turn to high-angle grain boundaries during deformation. The expression of the size of recrystallized grains D-r and parameter Z is obtained by regression analysis as In D-r=8.79964-0.33663ln Z. All the deformed samples present strong < 001 > and weak < 111 > fiber texture. With the increasing of temperature and decreasing of strain rate, the < 001 > texture strengthens gradually and < 111 > texture weakens gradually until extinction. (C) 2013 Elsevier B.V. All rights reserved.