Differential scanning calorimetry study and computer modeling of β ⇒ α phase transformation in a Ti-6Al-4V alloy
Differential scanning calorimetry study and computer modeling of β ⇒ α phase transformation in a Ti-6Al-4V alloy
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DOI：
10.1007/s11661-001-0345-x
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发表时间：
2001-04-01
影响因子：
2.8
通讯作者：
Wilson, A
中科院分区：
文献类型：
--
作者：
Malinov, S;Guo, Z;Wilson, A
迄今为止，钛合金热处理参数与微观结构之间的关系主要是利用显微镜等表征技术进行实证研究。相变动力学的计算和建模尚未广泛用于这些合金。差示扫描量热法（DSC）已广泛用于研究各种相变。基于 DSC 研究的结果，在不同系统的相变动力学的计算和建模方面已经做了很多工作。在本工作中，使用 DSC 研究了 Ti-6A1-4V 钛合金在 5 ℃、10 ℃、20 ℃、30 ℃、40 ℃和 50 ℃/min 恒定冷却速率的连续冷却条件下，β 双右箭头 α 相变的动力学。然后使用量热法的结果来追踪和模拟连续冷却条件下的转变动力学。根据适当解释的 DSC 结果，用异构转化分数线计算连续冷却转化 (CCT) 图。使用 Johnson-Mehl-Avrami (JMA) 理论并应用“可加性概念”对转化动力学进行建模。推导了 JMA 动力学参数。计算结果与实验转化分数之间表现出良好的一致性。使用导出的动力学参数，可以描述任何冷却路径和条件下 Ti-6A1-4V 合金中的 β 双右箭头 α 转变。还从成核活化能的角度对结果进行了解释。
The relationship between heat-treatment parameters and microstructure in titanium alloys has so far been mainly studied empirically, using characterization techniques such as microscopy. Calculation and modeling of the kinetics of phase transformation have not yet been widely used for these alloys. Differential scanning calorimetry (DSC) has been widely used for the study of a variety of phase transformations. There has been much work done on the calculation and modeling of the kinetics of phase transformations for different systems based on the results from DSC study. In the present work, the kinetics of the beta double right arrow alpha transformation in a Ti-6A1-4V titanium alloy were studied using DSC, at continuous cooling conditions with constant cooling rates of 5 degreesC, 10 degreesC, 20 degreesC, 30 degreesC, 40 degreesC, and 50 degreesC/min. The results from calorimetry were then used to trace and model the transformation kinetics in continuous cooling conditions. Based on suitably interpreted DSC results, continuous cooling-transformation (CCT) diagrams were calculated with lines of isotransformed fraction. The kinetics of transformation were modeled using the Johnson-Mehl-Avrami (JMA) theory and by applying the "concept of additivity." The JMA kinetic parameters were derived. Good agreement between the calculated and experimental transformed fractions is demonstrated. Using the derived kinetic parameters, the beta double right arrow alpha transformation in a Ti-6A1-4V alloy can be described for any cooling path and condition. An interpretation of the results from the point of view of activation energy for nucleation is also presented.