反应烧结B4C/Al2O3复合陶瓷的装甲防护性能研究

以B₂O₃、Al、石墨和B₄C粉体为原料, 采用反应-热压烧结工艺在1800℃/35 MPa的烧结条件下制备了致密的碳化硼基复相陶瓷, 对复相陶瓷的显微组织、物相组成、硬度、抗弯强度以及断裂韧性进行了观察与测试, 采用7.62 mm口径的穿甲弹分别对约束状态下和自由状态下的复相陶瓷靶板进行了剩余穿深试验(DOP), 并以AZ陶瓷和B₄C陶瓷为对比靶板, 根据剩余穿深结果计算了各自的防护系数。结果表明, 复相陶瓷的主要成分为B₄C和Al₂O₃, 其中主相B₄C约占70wt%, 第二相Al₂O₃约占30wt%, 由Al-B-O共同构成的复杂中间相填充在主相与第二相之间; 复相陶瓷的密度、硬度、抗弯强度和断裂韧性分别为2.82 g/cm³, 41.5 GPa, 380 MPa和3.9 MPa•m^1/2, 其中断裂韧性比纯碳化硼陶瓷提高了85.7%; 复相陶瓷的防护系数为7.34, 比AZ陶瓷和碳化硼陶瓷分别提高了11%和70%; 在约束状态下, 各个样品的防护系数比自由状态均提高10%。

Ballistic Performance of B4C/Al2O3 Composite Ceramic Prepared by Reaction Sintering

Dense B₄C ceramic matrix composites were synthesized by reactive hot press sintering at the temperature of 1800℃ and the pressure of 35 MPa using commercial available B₂O₃, Al, graphite, and B₄C as raw materials. Microstructure, phase composition and mechanical properties were observed and tested. The composite ceramics were penetrated by a 7.62 mm calibre armor-piercing bullet at restrained and unrestrained states. Then the protection factor was calculated according to the rules of DOP method. In comparison, the ballistic performances of AZ ceramic and monolithic B₄C were also investigated. The results indicated that the main phase of the as-prepared sample was B₄C (~70wt%) and the secondary phase was Al₂O₃. A complex intermediate phase contained Al-B-O was found filled in the holes between the main phase and the secondary phase. Density, hardness, bending strength and fracture toughness of the composite were 2.82 g/cm³, 41.5 GPa, 380 Mpa, and 3.9 MPa•m^1/2, respectively. The fracture toughness significantly increased by 85.7s% as compared with that of the pure B₄C (2.1 MPa•m^1/2). The protection factor of the composite ceramic gets 11% and 70% increase compared to those of AZ ceramic and monolithic B₄C, respectively. At restrained states, the protection factors of all the samples are further improved by about 10%. These results suggested that B₄C/Al₂O₃ composite ceramic prepared by reactive hot press sintering method might be a good ceramic armor material.