Si3N4/BN复合材料界面应变能释放速率的测试与表征

提出了一种更为合理、简便地测试与表征Si3N4／BN复合材料界面应变能释放速率的方法，借助流延成形和热压烧结工艺，制备出具有单一界面层“三期治”结构，在单侧基体中点处预制有裂纹源的Si3N4／BN／Si3N试样，用四点结弯曲加载的方法测出其载荷－位移曲线，进一步求出界面的应变能释放速率值，分别测出了BN＋Si3N4，BN Al2O3两种界面体系、不同成分界面的应变能释放速率值，对于纯BN，含积分数分别为15％，25％Si3N4调节的界面，其相应的应变能释放速率值分别为37．16，90．58，117．76J／m^2；含体积分数分别为16％，36％，63％Al2O3调节剂的界面，临界应变能释放速率值分别为53．95，71．86，119．21J／m^3，试验结果证明了该种方法的可行性及可靠性，与文献所报道的方法进行了对比、分析，同时分析了相关因素对实验结果的影响。

MEASUREMENT AND CHARACTERIZATION OF INTERFACIAL STRAIN ENERGY RELEASE RATE OF Si3N4/BN COMPOSITES BY FOUR-POINT BENDING TEST

A new method was developed to measure the interfacial strain energy release rate of Si 3N 4/BN composites. A kind of sandwich material with a single interlayer was designed and prepared by using the tape casting and hot press processing. The source of crack directly connecting the interface was preset on one of the Si 3N 4 matrices. The load-displacement curves were obtained by four_point bending test and the interfacial toughness was calculated on the basis of the fracture model of laminated composite. The interfacial toughness of Si 3N 4/BN composites modified with Si 3N 4 and Al 2O 3 were measured and characterized respectively. The strain energy release rate pure BN of is 37.16 J/m 2. For BN interphases modified with 15%, 25% volume fraction of Si 3N 4, the release rates are 90.58 J/m 2 and 117.76 J/m 2 respectively. For Al 2O 3 modified interphases with 16%, 36%, and 63% volume fraction, the corresponding critical strain energy release rates are 53.95 J/ m 2, 71.86 J/ m 2, and 119.21 J/ m 2 respectively. The advantages and disadvantages of the new method in comparison with other methods are discussed.