预制长度可控的裂纹以及原位观察裂纹扩展是研究陶瓷薄基板抗断裂行为的两大重点。本研究提出应变诱导法, 通过将基板与黄铜梁粘结形成复合体, 利用黄铜梁弯曲变形带动侧面陶瓷薄板受拉侧拉伸变形产生可控裂纹。在工具显微镜下对复合体进行四点弯曲, 原位观察样品的裂纹扩展情况, 通过调节黄铜梁宽度来控制初始裂纹长度, 在初始裂纹萌发后继续加载, 使裂纹达到测试断裂韧性的标准长度。将这种测试方法与块体材料断裂韧性的测试标准进行了对比, 结果表明: 采用该方法预制裂纹后测试断裂韧性具有简易性和可靠性。应变诱导法预制裂纹成功率高, 裂纹萌发位置及长度可控, 且操作方便, 可推广应用于超薄玻璃等其他超薄脆性材料的断裂韧性评价和分析裂纹扩展阻力。

Controllable length of pre-crack and in-situ observation are two major difficulties in the research of fracture resistance of ceramic materials. In this study, a method of strain-induced cracking was proposed, in which the plate was bonded to a brass beam to form a composite. The bending deformation of brass beam derived the tension deformation in the tension zone of ceramic thin plate to induce the controllable crack. Four-point bending test was conducted under a tool microscope to perform in-situ observation of crack propagation. The initial crack length was controlled by adjusting the width of the tensile zone of the ceramic plate. After the crack initiation, loading continued to make the crack length meet the requirements of fracture toughness test for ceramics. Compared with standard test of fracture toughness of block materials, the above method is simple and reliable. The strain-induced method to pre-crack has high success rate, the position of crack initiation and the length of pre-crack are controllable and easy to operate. It can be widely applied to fracture toughness evaluation and crack propagation resistance analysis of ultra-thin glass and other ultra-thin brittle materials.