AlN/堇青石基玻璃陶瓷复合材料的显微组织与力学性能

Microstructure and mechanical properties of AlN/cordierite-based glass-ceramic composites

用真空热压烧结法制备AlN/堇青石玻璃陶瓷复合材料。分析复合材料样品的相对密度、抗弯强度和断裂韧度与AlN含量及烧结温度的关系,并对其显微组织与力学性能进行研究。结果表明:样品的相对密度随AlN加入量的增加逐渐下降;样品的抗弯强度和断裂韧度随烧结温度的升高而增加,随AlN加入量的增加呈先升后降的变化趋势;当AlN体积分数为0.40时,复合材料样品的抗弯强度和断裂韧性达到最大值,分别为212 MPa和3.04 MPa.m1/2。XRD分析表明:AlN与堇青石玻璃未发生化学反应,化学相容性好。断口形貌和压痕裂纹扩展路径的扫描电镜观察结果表明,复合材料的强化机制主要是载荷传递,增韧机制主要为裂纹的绕道偏转、分叉和钉扎与颗粒的拔出。

AlN/cordierite glass-ceramic composites were prepared by vacuum hot-pressing process. The relative density, flexural strength and fracture toughness of the composites as a function of the content of AlN and sintering temperature were investigated. The mechanical properties and microstructure of the composites were also studied. The results show that the relative density of the samples decreases slowly with the addition of AlN. The flexural strength and fracture toughness of the samples increase with rising firing temperature. However, they increase firstly and then decrease with increasing AlN content. The flexural strength and fracture strength of the composites doped with 40% AlN（volume fraction） reach 212 MPa and 3.04 MPa.m^1/2, respectively. XRD analysis indicates that no chemical reaction occurs between the cordierite-based glass matrix and AlN particles, which suggests that the glass matrix have excellent chemical compatibility with AlN particles. The main strengthening mechanism is load transfer. And the main toughening mechanisms are deflexion, divarication and transfixion as well as AlN particles pulling out.