In-service Catastrophic Failure: or Controlling the Grain Boundary Network Evolution

硬质合金刀具是我们依赖于切割、铣削、钻孔和车削的生产行业的关键。硬质合金(WC-Co)是最重要的粉末冶金刀具加工材料之一。这是因为与聚晶钻石等替代品相比，它具有优异的硬度/耐磨性和韧性，且成本较低。然而，在使用期间(例如在机械加工中)，复合材料结构受到高机械和热载荷的组合，其中硬质碳化物颗粒通过软钴粘结剂连接，变形直到过度磨损和断裂降低了性能和寿命。在低钴含量时，WC-Co中的裂纹路径主要沿着WC/WC和WC/Co的晶界和相界。虽然WC晶界特征，即晶界网络，是不同掺杂硬质合金2-5的特征，但缺乏关于晶界网络如何在使用过程中演变并最终允许沿晶界形成裂纹的知识。

Hardmetal tools are a key for our production industries relying on cutting, milling, drilling, and turning. Cemented carbides (WC-Co) are one of the most prominent powder metallurgy processed materials use for cutting tool applications. This is due to a combination of excellent hardness/wear resistance and toughness with low cost compared to alternatives such as polycrystalline diamond. During service (e.g. in machining) , however, the composite structure is subjected to a combination of high mechanical and thermal loads, where hard carbide particles are joint by soft cobalt binder, deforms until excessive wear and fracture reduce the performance and lifetime. Crack paths in WC-Co predominantly follow WC/WC and WC/Co grain and phase boundaries at low cobalt concentrations1. While the WC grain boundary character, the grain boundary network, is characterised for differently doped cemented carbides2-5, knowledge of how the grain boundary network evolves during service and ultimately allows for crack formation along grain boundaries is absent.