激光切口法测量ZrB2–SiC–Graphite陶瓷的断裂韧性

Accurate Measurement of Fracture Toughness in ZrB2–SiC–Graphite Ceramic via Laser Notching Method

采用纳秒激光在ZrB2-SiC-Graphite(ZSG)陶瓷材料中引入了尖锐的V型切口,切口尖端半径小于1μm。通过单边V型切口梁法测得ZSG陶瓷材料的断裂韧性为3.88MPa·m^1/2,与单边预裂纹梁法结果吻合,表明激光切口法的有效性。研究了断裂韧性与激光切口深度和试样厚度比值(a/W)的关系,对于ZSG陶瓷,试样的a/W取值范围为0.1~0.6时能获得准确的断裂韧性值。

Sharp V-notches with tip radius less than 1 μm were introduced in the ZrB2-SiC-Graphite(ZSG) ceramic via a nanosecond laser. The fracture toughness of ZSG ceramic measured by a single-edge V-notched beam method is 3.88 MPa·m^1/2, which is in reasonable agreement with that by a single-edge precracked beam method. In addition, fracture toughness values of test samples with different ratios of notch depths to sample heights(a/W) were also investigated. The results show that accurate fracture toughness value of ZSG ceramic can be obtained when the a/W value is in the range of 0.1-0.6.