Thermodynamic modeling of Cr-AI-C and Ni-AI-C systems for low-density steels
Thermodynamic modeling of Cr-AI-C and Ni-AI-C systems for low-density steels
复制标题
低密度钢 Cr-AI-C 和 Ni-AI-C 体系的热力学建模
DOI：
10.1007/s42243-020-00415-y
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发表时间：
2020
影响因子：
2.5
通讯作者：
Lu Xiaogang
中科院分区：
文献类型：
--
作者：
Zheng Weisen;He Yanlin;Lu Xiaogang
低密度钢由于添加了轻元素Al而具有高的比强度和延展性，引起了人们的广泛兴趣。为了加速低密度钢的设计，作者组开发了一个热力学数据库。两种含铝体系，即，在可靠的二元描述基础上，采用CALPHAD方法对Cr-Al-C和Ni-Al-C进行了建模和优化。对于Cr-Al-C系，利用热容的实验数据，用与温度相关的多项式描述了Cr_2AlC相的吉布斯自由能，而不是用Neumann-Kopp规则估算热容。Cr_2AlC的异成分熔化温度为1762 K，反应为液相+ Cr_3C_2 + Al_4C_3 → Cr_2AlC。用该模型参数较好地再现了Cr_2AlC与二元相之间的相平衡。对于Ni-Al-C体系，根据碳在液相、面心立方相和体心立方相中的溶解度，对液相、面心立方相和体心立方相进行了优化。用本文对Ni-Al-C系的描述得到了计算值与实验值之间的良好一致。在本工作中开发的两个三元系的可靠的描述可以实施到低密度钢的热力学数据库。
The so-called low-density steels have generated a lot of interests with their high specific strength and ductility due to the addition of the light element Al. In order to accelerate the low-density steel design, a thermodynamic database has been developed within the present author group. Two Al-containing systems, i.e., Cr-Al-C and Ni-Al-C,were modeled and optimized with CALPHAD approach based on the reliable binary descriptions. For Cr-Al-C system, the Gibbs energy of Cr_2AlC phase was described by a temperature-dependent polynomial with the aid of the experimental data on the heat capacity, instead of estimating heat capacity from Neumann-Kopp rule. The incongruent melting temperature of Cr_2AlC is 1762 K with the invariant reaction of liquid + Cr_3C_2 + Al_4C_3 → Cr_2AlC. The phase equilibria between Cr_2AlC and binary phases were well reproduced by using the present model parameters. For Ni-Al-C system, the liquid, fcc and bcc phases have been optimized to fit the carbon solubility in these three phases. A good agreement between the calculated and experimental data has been obtained using the present description of Ni-Al-C system. The reliable descriptions of the two ternary systems developed in the present work can be implemented into the thermodynamic database for low-density steels.