Xuemei Ouyang , Quan wang , Fucheng Yin , Yuling Shi , Jingxian Hu
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引用次数: 0
摘要
B-Co-Ti 三元体系的相平衡对于制备和开发含 Co 的 TiB2 基陶瓷非常重要。为了获得液相投影,通过电弧熔炼制备了 54 种铸造合金。通过扫描电子显微镜、电子探针显微分析、X 射线衍射和差示扫描量热法分析了 54 种合金的微观结构和凝固路径。结果表明,B-Co-Ti 三元体系的液相投影包含 15 个主要析出区:BCC、CoTi2、CoTi、Co2Ti、Co3Ti、αCo、TiB、Ti3B4、TiB2、(B)、CoB、Co2B、Co3B、τ1 和 τ2。根据实验数据提出了六种 E 型和九种 U 型三元不变反应。对 B-Co-Ti 三元体系进行了热力学计算,得到了一组自洽的热力学参数。计算得到的液相投影和 800 °C 等温截面与实验数据十分吻合。
Experimental investigation and thermodynamic calculation of the B-Co-Ti ternary system
The phase equilibrium of the B-Co-Ti ternary system is important for the preparation and development of Co-containing TiB2-based ceramics. To obtain the liquidus projection, 54 kinds of as-cast alloys were prepared via arc melting. The microstructures and solidification paths of the 54 kinds of alloys were analyzed by scanning electron microscopy, electron probe microanalysis, X-ray diffraction and differential scanning calorimetry. The results show that the proposed liquidus projection of the B-Co-Ti ternary system contains 15 primary precipitation regions: BCC, CoTi2, CoTi, Co2Ti, Co3Ti, αCo, TiB, Ti3B4, TiB2, (B), CoB, Co2B, Co3B, τ1 and τ2. Six E-type and nine U-type ternary invariant reactions are suggested on the basis of experimental data. The thermodynamic calculation of the B-Co-Ti ternary system was carried out, and a set of self-consistent thermodynamic parameters was obtained. The calculated liquidus projection and 800 °C isothermal sections are in good agreement with the experimental data.
期刊介绍:
The design of industrial processes requires reliable thermodynamic data. CALPHAD (Computer Coupling of Phase Diagrams and Thermochemistry) aims to promote computational thermodynamics through development of models to represent thermodynamic properties for various phases which permit prediction of properties of multicomponent systems from those of binary and ternary subsystems, critical assessment of data and their incorporation into self-consistent databases, development of software to optimize and derive thermodynamic parameters and the development and use of databanks for calculations to improve understanding of various industrial and technological processes. This work is disseminated through the CALPHAD journal and its annual conference.