热压B4C—C陶瓷复合材料的组织与性能

Microstructure and Mechanical Properties of B4C C Ceramic

摘要:

研究了添加游离碳含量对碳化物粉末的热压烧结行为及对Ｂ４Ｃ－Ｃ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）的碳化颗烧结体的相对密度可高达９８．５％，断裂韧性为７．６５ＭＰａ．ｍ＾１／２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

Abstract:

The effect of free carbon on the hotpressing behavior of boron carbide powders, flexural strength and toughness of hotpressed boroncarbide ceramic materials is studied. The composition, microstructure and fracture behavior of hotpressed ceramic materials were examined and analyzed using Xray diffraction and SEM. The experimental results show that density and properties of sintered materials are depended on additive carbon content in powders. For a certain hotpressing conditions, relative density, flexural strength and fracture toughness of the materials hotpressed from boron carbide powder with 7wt% carbon are 985%, 460 MPa and 765 MPam1/2,respectively. From the analyses of compositions and fracture surface, it is found that crack branching and blunting are the main reasons for flexural strength decrease and fracture toughness increase with the increase of the carbon content.