传统压痕法识别陶瓷材料断裂韧性的有效性研究

基于虚拟裂纹闭合法对传统压痕法测试陶瓷材料断裂韧性的数值模型进行计算,以此为基础,分析比较传统压痕法的几种典型公式识别陶瓷材料断裂韧性的测试误差和所测材料的适用范围。结果表明:传统压痕法的Anstis公式较Evans公式,Lawn公式,JISR公式和Niihara公式,在材料比功0.3≤We/Wt≤0.45时所测断裂韧性值与理论计算值较为接近,其最大误差为12.9%,测试结果相对准确;当0.45We/Wt≤0.7时,传统压痕法对陶瓷材料断裂韧性的测试误差随比功增加迅速增大,特别是当We/Wt=0.7时,Anstis公式,Evans公式,Lawn公式,JISR公式和Niihara公式所测断裂韧性值与理论计算值的最大误差分别为70%,148.5%,48.8%,98.7%和166.6%,在此材料比功范围内传统压痕法所测断裂韧性值误差较大。

Validity of Traditional Indentation Method for Evaluating Fracture Toughness of Ceramic Materials

The numerical model of evaluating ceramics’fracture toughness by traditional indentation method was calculated with the application of virtual crack closure technique,based on which,the measurement errors and application scope of several typical formulas employed in traditional indenta-tion method to evaluate the fracture toughness of ceramic materials were analyzed.The results show that,compared with Evans formula,Lawn formula,JISR formula and Niihara formula of traditional indentation method,the value of fracture toughness measured by using Anstis formula is closer to the theoretical value,enjoying relatively accurate testing results with a maximum error of 12.9%,when the material’s ratio of unloading work to total loading work fell 0.3≤W e/W t ≤0.45.When the mate-rial’s ratio of unloading work to total loading work ranged 0.45