ZrB_2颗粒增韧B_4C陶瓷的原位合成

In situ synthesis of B_4C ceramics toughened by ZrB_2 particles

采用机械混合法无压烧结原位合成ZrB_2/B_4C陶瓷复合材料,研究了ZrB_2含量对复相陶瓷主要性能的影响,分析了复相陶瓷的增韧机理．结果表明,当ZrB_2的体积分数为16%时,相对密度最大约为94%,维氏硬度为39．5 GPa,抗折强度为320 MPa,断裂韧性为3．10 MPa·m^(1/2)．由B_4C基体和ZrB_2颗粒热膨胀系数不匹配引起的裂纹偏转是ZrB_2/B_4C复相陶瓷增韧的主要原因．

ZrB2/B4C ceramics composites was in siut synthesized by mechanical mixing in conditions that pressuretess sintering. The effects of ZrB2 particle content on the main properties of ZrB2/B4C composites were investigated.. ,The toughening mechanism was analysed. The results showed that as addition of 16% ZrB2, the max relative density of composites is 94%T.D, vickers hardness is 39.5 GPa, bending strength is 320 MPa, fracture toughness is 3.10 MPa.m^1/2. The crack deflection caused by the difference in thermal expansion coefficient between the matrix B4C and the particle ZrB2 is the main mechanism responsible for the increase of toughness.