Carbon content dependence of grain growth mode in VC-doped WC-Co hardmetals
Carbon content dependence of grain growth mode in VC-doped WC-Co hardmetals
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DOI：
10.1016/j.ijrmhm.2015.07.002
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发表时间：
2015-09-01
影响因子：
3.6
通讯作者：
Yamamoto, T.
中科院分区：
文献类型：
--
作者：
Sugiyama, I.;Mizumukai, Y.;Yamamoto, T.
研究了vc掺杂WC-Co硬质合金中碳含量对晶粒生长机理的依赖性和晶粒生长抑制机理。采用液相烧结方法对三种不同碳含量的vc掺杂WC-Co硬质合金进行快速淬火，使其在烧结温度下凝固。在这些样品中，利用透射电子显微镜（TEM）和相关技术研究了富v相的空间分布和原子尺度结构。在这些测量中，掺杂的V以溶质的形式存在于液相中，在大的（W，V）C-X析出物和界面分离中存在。对WC晶/Co相界面上的（W，V）C-X偏析进行了进一步的详细观察和讨论。这些（W，V）C-X相根据碳的含量从平面薄膜转变成小岛屿。在低碳样品中，WC晶粒/Co相界面被平面（W，V）C-X完全覆盖。另一方面，在高碳含量材料中，WC晶粒/Co相界面部分被（W，V）C-X岛覆盖。烧结过程中，WC晶粒的生长速度明显快于低碳样品。这些结构差异是用WC晶粒/(W，V)C-X界面能来讨论的。(C) 2015 Elsevier Ltd.版权所有。
Carbon content dependency of grain growth mechanism and grain growth inhibition mechanism in VC-doped WC-Co hardmetals is investigated. VC-doped WC-Co hardmetals with three different carbon contents were sintered with liquid phase and then rapidly quenched to freeze up the structure at the sintering temperature. In these samples, spatial distributions and atomic scale structures of V-rich phases are investigated using transmission electron microscopy (TEM) and related techniques. In these measurements, doped V is found in liquid phase as solute, in large (W,V)C-X precipitates and in interface segregations. Further detailed observations and discussions are carried out for the (W,V)C-X segregated at the WC grain/Co phase interfaces. These (W,V)C-X phases change their form from planar films to small islands depending on the carbon content. The WC grain/Co phase interfaces are fully covered by planar (W,V)C-X in the sample of low carbon content. On the other hand, the WC grain/Co phase interfaces are partially covered by (W,V)C-X islands in the material of high carbon content. During sintering, the WC grains in this sample grew much faster than those in the sample of low carbon content. These structural differences are discussed in terms of WC grain/(W,V)C-X interface energy. (C) 2015 Elsevier Ltd. All rights reserved.