热压多孔碳化硼的力学性能及其影响因素

Mechanical properties and influence of hot-pressed porous boron carbide

用热压法制得了中等密度的碳化硼陶瓷,并测定了其抗弯强度、抗压强度、弹性(弯曲)模量、泊松比,得出了其抗弯强度、弹性模量与孔隙度的关系,以及抗弯强度与温度的关系.研究结果表明:所制的碳化硼陶瓷表观密度为2 1～2 3g/cm3,晶粒粒径为12μm,室温时平均抗弯强度为247 8MPa,抗压强度大于1250 7MPa,泊松比为0 16,表明材料的微观结构良好.在测量温度范围内,碳化硼的强度随温度的变化不大.

The mechanical properties are very important and related to nearly all the uses for boron carbide. But as many brittle ceramics, these properties are extremely sensitive to microstructure. Since the materials with the same structure can′t be obtained by controlling the process of manufacture, the formulae and data about mechanical properties reported by literatures are quite different. In this paper the bending strength, the compressive strength, the elastic (bending) modulus and poisson ratio of hotpressed porous boron carbide are measured and the relationship between bending strength and poisson ratio, elastic modulus and poisson ratio, bending strength and temperature are studied. The results show that when the density is 2.1～2.3 g/cm3 and the diameter of grain size is 12 μm, the average bending strength at room temperature is 247.8 MPa, the pressure strength is 1?250 MPa, the elastic modulus is 290.4 GPa, and the poisson ratio is 0.16, which states the microstructure of material is good. In the range of measurement temperature, the boron carbide′s value is nearly not changed.