Effects of tantalum on austenitic transformation kinetics of RAFM steel
Effects of tantalum on austenitic transformation kinetics of RAFM steel
复制标题
钽对 RAFM 钢奥氏体转变动力学的影响
DOI：
10.1016/s1006-706x(17)30106-1
复制
发表时间：
2017-07-01
影响因子：
2.5
通讯作者：
Li, Hui-jun
中科院分区：
文献类型：
--
作者：
Chen, Jian-guo;Liu, Yong-chang;Li, Hui-jun
研究了不同钽含量(0 wt.%，0.027wt.%，0.073wt.%)被设计和铸造。采用差示扫描量热法和光学显微镜研究了钽含量对RAFM钢奥氏体相变的影响。用相变模型描述了奥氏体相变动力学。该模型是在经典的Johnson-Mehl-Avrami-Kolmogorov模型的基础上建立的，包括位饱和成核、扩散控制生长和碰撞修正。通过对实验数据的拟合和动力学模型的建立，计算了指前扩散因子DO和扩散激活能Q(D)等相变动力学参数。结果表明，随着Ta含量的增加，平均晶粒度减小。随着Ta含量的增加，A(C1)和A(C3)(奥氏体相变开始温度和结束温度)的值都增大。Ta的增加导致了D-0的降低。但Q(D)随Ta的增加而增大。此外，作为碳化物形成元素，Ta会降低碳的扩散系数，减缓奥氏体相变速率。
The RAFM (reduced activation ferritic/martensitic) steels containing different tantalum contents (0 wt. %, 0. 027 wt. %, 0. 073 wt. %) were designed and cast. Differential scanning calorimetry and optical microscopy were employed to explore the influence of tantalum content on the austenitic transformation of RAFM steels. The austenitic transformation kinetics was described by a phase-transformation model. The model, involving site saturation nucleation, diffusion-controlled growth and impingement correction, was established based on the classical Johnson-Mehl-Avrami-Kolmogorov model. The phase-transformation kinetics parameters, including Do (pre-exponential factor for diffusion) and Q(d) (activation energy for diffusion), were calculated by fitting the experimental data and the kinetic model. The results indicated that the average grain size is decreased with the increase of tantalum. The values of A(c1), and A(c3) (onset and finish temperature of austenitic transformation, respectively) are increased by increasing the tantalum content. The increase of tantalum caused the decrease of D-0. However, Q(d) is increased with the increase of tantalum. In addition, as a carbides forming element, tantalum would reduce the carbon diffusion coefficient and slow down the austenitic transformation rate.