Ma Taoran, Borrajo-Pelaez Rafael, Hedström Peter, Blomqvist Andreas, Borgh Ida, Norgren Susanne, Odqvist Joakim
Department of Materials Science and Engineering, KTH Royal Institute of Technology, Stockholm SE-100 44, Sweden.
Sandvik Coromant Research and Development, Stockholm SE-126 80, Sweden.
Materials (Basel). 2017 Jan 11;10(1):57. doi: 10.3390/ma10010057.
(Ti,Zr)C powder was sintered with WC-Co following an industrial process, including an isotherm at 1410 °C. A series of interrupted sintering trials was performed with the aim of studying the sintering behavior and the microstructural evolution during both solid-state and liquid-state sintering. Reference samples, using the same elemental compositions but with the starting components TiC and ZrC instead of (Ti,Zr)C, were also sintered. The microstructure was investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. It is found that the (Ti,Zr)C phase decomposes into Ti-rich and Zr-rich nano-scale lamellae before the liquid-state of the sintering initiates. The final microstructure consists of the binder and WC as well as two different γ phases, rich in either Ti (γ₁) or Zr (γ₂). The γ₂ phase grains have a core-shell structure with a (Ti,Zr)C core following the full sintering cycle. The major differences observed in (Ti,Zr)C with respect to the reference samples after the full sintering cycle were the referred core-shell structure and the carbide grain sizes; additionally, the microstructural evolution during sintering differs. The grain size of carbides (WC, γ₁, and γ₂) is about 10% smaller in WC-(Ti,Zr)C-Co than WC-TiC-ZrC-Co. The shrinkage behavior and hardness of both composites are reported and discussed.
(Ti,Zr)C粉末与WC-Co按照工业流程进行烧结，包括在1410℃下的等温过程。进行了一系列间断烧结试验，目的是研究固态和液态烧结过程中的烧结行为和微观结构演变。还烧结了参考样品，其使用相同的元素组成，但起始成分是TiC和ZrC而不是(Ti,Zr)C。使用扫描电子显微镜和能量色散X射线光谱对微观结构进行了研究。发现(Ti,Zr)C相在烧结的液态开始之前分解为富Ti和富Zr的纳米级薄片。最终的微观结构由粘结剂、WC以及两种不同的γ相组成，一种富含Ti(γ₁)，另一种富含Zr(γ₂)。在完整的烧结循环后，γ₂相晶粒具有核壳结构，其核心为(Ti,Zr)C。在完整的烧结循环后，(Ti,Zr)C与参考样品相比观察到的主要差异是上述的核壳结构和碳化物晶粒尺寸；此外，烧结过程中的微观结构演变也不同。WC-(Ti,Zr)C-Co中碳化物(WC、γ₁和γ₂)的晶粒尺寸比WC-TiC-ZrC-Co小约10%。报告并讨论了两种复合材料的收缩行为和硬度。
