Grain growth and hardness of TiC-based cermets: Experimental investigation and thermodynamic calculations
Grain growth and hardness of TiC-based cermets: Experimental investigation and thermodynamic calculations
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TiC 基金属陶瓷的晶粒生长和硬度：实验研究和热力学计算
DOI：
10.1016/j.ceramint.2016.09.096
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发表时间：
2016-12-01
影响因子：
5.2
通讯作者：
Wang, Jiong
中科院分区：
文献类型：
--
作者：
Zhang, Cong;Du, Yong;Wang, Jiong
通过实验测定和热力学计算，系统研究了Mo、W添加量和烧结时间对TiC基金属陶瓷显微组织、晶粒长大和硬度的影响。在计算的碳窗口的指导下，设计了不同Mo和W含量的TiC基金属陶瓷，并在1430 ℃、Ar气氛下分别烧结0、1、2和5 h。采用扫描电子显微镜（SEM）观察了金属陶瓷的显微组织，采用ImageJ软件测量了陶瓷相的体积分数和平均晶粒尺寸。Mo和W的加入降低了陶瓷相的体积分数，表明Mo和W对碳化物的溶解有促进作用。晶粒生长动力学遵循立方规律，由溶解原子通过液态粘结相的扩散控制（即Ostwald熟化机制）。在TiC基金属陶瓷中添加Mo和W可导致液相烧结过程中的缓慢晶粒生长过程。此外，还对金属陶瓷的维氏硬度进行了测试，结果表明，粘结相的体积分数和组成、陶瓷相的平均晶粒尺寸以及界面结合强度等因素对硬度有影响。
In the present work, the influence of Mo and W additions and sintering time on the microstructure, grain growth and hardness of TiC-based cermets was systematically investigated by means of experimental determination and thermodynamic calculations. Under the guidance of the calculated carbon window, the TiC-based cermets with different Mo and W contents have been designed and sintered at 1430 degrees C in Ar atmosphere for 0 h, 1 h, 2 h and 5 h. The microstructure of cermets was observed by using scanning electron microscopy (SEM), while the volume fraction and average grain size of ceramic phase were measured by using ImageJ software. The volume fraction of ceramic phase decreases with the addition of Mo and W, which indicates the promoting effect of Mo and W on the carbide dissolution. The grain growth kinetics followed the cubic law, which was controlled by the diffusion of dissolved atoms through liquid binder phase (i.e. Ostwald ripening mechanism). The addition of Mo and W in TiC-based cermets can lead to a slow grain growth process during liquid-phase sintering. In addition, the Vicker hardness measurement was performed for the cermets, and the hardness was influenced by several factors, such as volume fraction and composition of binder phase, average grain size of ceramic phase and bonding strength of interface.