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研究了添加游离碳含量对碳化硼粉末的热压烧结行为及对Ｂ４ＣＣ陶瓷的强度和断裂韧性的影响．用Ｘ射线衍射、扫描电镜对烧结体的成分、显微结构和断裂行为进行了分析讨论．结果表明：在一定的热压条件下，添加７％Ｃ（质量分数）的碳化硼烧结体的相对密度可高达９８．５％，断裂韧性为７．６５ＭＰａ·ｍ１／２，弯曲强度仍能达４６０ＭＰａ．通过成分及断口形貌观察，由于晶界Ｃ对晶界的弱化及晶界的分层诱韧化作用使裂纹偏转、钝化可能是造成热压碳化硼随添加碳含量的增多，其强度下降和韧性升高的主要机制．
The effects of adding free carbon on the hot-pressing sintering behavior of boron carbide powder and the strength and fracture toughness of B4CC ceramics were investigated. The composition, microstructure and fracture behavior of the sintered body were analyzed and discussed by X-ray diffraction and scanning electron microscopy. The results show that under certain hot pressing conditions, the relative density of boron carbide sintered body with 7% C (mass fraction) can be as high as 98.5% and the fracture toughness is 7.65MPa · m1 / 2, the flexural strength can reach 460MPa. Through the observation of the composition and the fracture morphology, the crack is deflected due to the weakening of the grain boundary C and the delamination-induced tempering of the grain boundary. The passivation may be caused by the increase of hot pressed boron carbide with the increase of the added carbon content and the decrease of its strength And the main mechanism of increased toughness.