Ti_3SiC_2添加剂对B_4C陶瓷组成、结构与性能的影响

Influence of Ti_3SiC_2 additive on the composition,structure and properties of B_4C ceramics

为了提高B4C陶瓷的力学性能,本文以三元化合物钛硅碳(Ti3SiC2)为添加剂,在温度2100℃,压力25MPa条件下热压反应烧结制备B4C-TiB2陶瓷。研究了Ti3SiC2不同添加量对B4C-TiB2陶瓷组成、结构与性能的影响。结果表明,1100℃时,Ti3SiC2与B4C开始反应生成TiB2颗粒,1300℃时反应完全,TiB2颗粒主要位于三角晶界处,少数颗粒位于B4C晶粒内。TiB2弥散增强以及TiB2热膨胀系数与基体不匹配产生的残余应力和裂纹偏转提高了B4C-TiB2陶瓷的力学性能。当Ti3SiC2添加量为10mass%时,B4C-TiB2陶瓷密度、三点弯曲强度、断裂韧性和显微硬度分别为2.64g/cm3、592MPa、7.01MPa·m1/2、3163kg/mm2。

In order to improve the mechanical properties of B4 C ceramic,B4 C-TiB2 ceramics was fabricated by reactive hot pressing at 2100℃,25MPa with Ti3 SiC2 as additive in the paper.The Effect of Ti3 SiC2 with different mass fraction on composition,microstructure and properties of TiB2-B4 Cceramic was studied.The results show that Ti3 SiC2 begins to react with B4 C and generate TiB2 particle at 1100 ℃,the reaction is ended at 1300 ℃.TiB2 particles mainly locate in the triangle grain boundary and few locate inside the B4C grain.The improvement of the mechanical properties of B4 C-TiB2 ceramics is attribute to TiB2 particles dispersing in the matrix,residual stress and crack deflection generated by the coefficient of thermal expansion between TiB2and B4C.When the mass fraction of Ti3 SiC2 is up to 10%,the density,three-point bending strength,fracture toughness,and hardness of B4 C-TiB2 ceramics are 2.64g/cm3,592MPa,7.01MPa.m1/2 and 31630kg/mm2 respectively.