The main goal of this work is to obtain a reliable value of the fracture toughness of single grains of tungsten carbide (WC). It is attempted by testing microcantilever and micropillar samples shaped out, by means of focused ion beam milling, of individual WC particles embedded within a WC-Co cemented carbide grade. Experimental testing included the use of a nanoindenter for inducing microcantilever bending and micropillar splitting, as well as sampling WC grains with basal and prismatic orientations. Experimental results are compared with those previously assessed through implementation of the indentation microfracture technique. Bending of notched microcantilevers yielded more consistent results than those measured out of micropillar splitting tests. In this regard, the average value of fracture toughness for single WC grains, within the two-phase interpenetrated network existing in cemented carbides, is found to be 5.6 ± 0.8 MPa·m^1/2. Such a relatively high value – coherent with local plastic features evidenced in nanoindentation imprints - is in satisfactory agreement with results indirectly estimated from other macromechanical tests.

这项工作的主要目的是获得碳化钨（WC）单晶粒的断裂韧性的可靠值。通过测试微悬臂梁和微柱状样品来进行尝试，这些样品通过聚焦离子束铣削加工而成，这些样品嵌入了WC-Co硬质合金牌号中的各个WC颗粒。实验测试包括使用纳米压头诱导微悬臂梁弯曲和微柱裂，以及对具有基向和棱柱取向的WC晶粒进行采样。将实验结果与先前通过压痕微断裂技术的实施进行评估的结果进行比较。缺口微悬臂弯曲产生的结果比微柱分裂试验测得的结果更一致。在这方面，单个WC晶粒的断裂韧性平均值，^1/2。如此高的价值-与纳米压痕印记所证明的局部塑性特征相一致-与其他宏观力学测试间接估计的结果令人满意。