(西安交通大学 材料科学与工程学院材料强度国家重点实验室,
西安 710049)
摘 要: 利用压痕-强度法测定了SiC/BN层状陶瓷的阻力曲线行为, 并与SiC单相陶瓷做对比。 结果表明: 2种材料均呈现出上升阻力曲线行为, 其中, SiC/BN层状陶瓷显示出更为优越的抗裂纹扩展能力, 其阻力曲线上升较陡, 上升幅度较大; SiC单相陶瓷的阻力曲线上升较缓且上升幅度较小。 分析认为, 这与其不同的增韧机制有关。 原位增韧是SiC单相材料韧性提高的主要原因, 而裂纹遇到弱界面时发生偏转、 分叉、 脱层等是层状陶瓷材料抗裂纹扩展能力提高的主要原因
关键字: 层状陶瓷; 阻力曲线; 压痕-弯曲强度法
(State Key Laboratory for Mechanical Behavior of Materials,
School of Materials Science and Engineering,
Xi′an Jiaotong University, Xi′an 710049, China)
Abstract:The R-curve of SiC/BN laminated ceramic was evaluated by the indentation-strength method and compared with that of monolithic SiC. The results show that the two materials possess up R-curve behaviors: a steep R-curve behavior for SiC/BN laminated ceramic, showing higher crack propagation resistance; a plateau R-curve behavior for monolithic SiC, which is closely related to their different toughening mechani, sms. In-situ toughening accounts for the fracture toughness increase of monolithic SiC, while, crack deflection, crack branching and crack delamination contribute to the higher fracture resistance of SiC/BN laminated ceramic.
Key words: laminated ceramics; resistance curve; indentation-strength in bending method