Matrix-body PDC bits endure the reactive shear force and impact damage during the rotary cutting of rock formations under downhole, making the bit blades vulnerable to premature breakage. To avoid the blade breakage, the key is to improve the fracture strength (also known as transverse rupture strength, TRS) of the matrix body of PDC bits. This work investigated the effects of size, shape, and type of tungsten carbides on fracture strength. Weibull distribution was adopted to describe the variations in the repeated TRS test results, which proved to be more appropriate than the normal distribution and could be used as an indirect indicator of the quality and performance of the matrix body. The results of this study showed that the median particle size is the predominant factor determining the TRS performance of the matrix body. Small-sized carbide particles deliver higher TRS, indicating that the fracture strength of the matrix body follows the Hall-Petch relation. Based on this finding, the fracture strength can be significantly reinforced to extend the service life of matrix-body PDC bits under harsh downhole conditions, leading to the reduction of trips and dramatic savings. However, the small-sized carbide particles are inherent lack of erosion resistance and accordingly limit their applications.

基体PDC钻头在井下旋转切割岩层时会承受反剪力和冲击损伤，使钻头刀片容易过早损坏。为了避免刀片断裂，关键是提高PDC钻头基体的断裂强度（也称为横向断裂强度，TRS）。这项工作研究了碳化钨的尺寸，形状和类型对断裂强度的影响。采用威布尔分布来描述重复TRS测试结果中的变化，事实证明这种变化比正态分布更合适，并且可以用作基质体质量和性能的间接指标。这项研究的结果表明，中值粒径是决定基体TRS性能的主要因素。小尺寸的碳化物颗粒可提供更高的TRS，表明基体的断裂强度遵循霍尔-帕奇关系。基于此发现，在恶劣的井下条件下，可以显着增强抗裂强度，以延长基体PDC钻头的使用寿命，从而减少跳闸次数并节省大量资金。但是，小尺寸的碳化物颗粒固有地缺乏耐腐蚀性，因此限制了它们的应用。