Microcrack Evolution in Alumina Ceramics: Experiment and Simulation

Thermal expansion induced spontaneous microcracking in large‐grained polycrystalline alumina was analyzed using experimental techniques as well as numerical simulations. A microstructure‐based finite‐element model (object oriented finite‐element analysis) was used to simulate the accumulation of microcrack damage upon cooling, taking the measured real crystallographic orientations of the grains into account. Crack initiation and propagation were simulated using a Griffith‐type fracture criterion. The computed evolution of Young's modulus as a function of temperature and grain size was compared with the corresponding experimental results.