FIB Tomographic Analysis of Subsurface Indentation Crack Interactions with Pores in Alumina

摘要

This article describes a study involving three-dimensional FIB tomographic characterization of Vickers microindentation sites in an alumina material containing pores. The study was carried out using a dual beam FIB instrument for loads in the range 50-200 g. The results obtained show that this technique can be used to obtain 3-D distributions of indentation-generated cracks. Although, compared to a dense material, presence of pores in alumina reduced the ability to generate and/or propagate radial cracks, the significant probability of crack-pore interactions indicates that pores assist in the generation/propagation lateral cracks. The subsurface images show that pores act as sites for crack initiation and/or assist in crack propagation. In addition, a clearly reduced ability to generate and/or propagate radial cracks has been noted. However, considering that FIB tomography is destructive and invasive, microstruc-tural changes seem to have occurred during the process and consequently it is not possible to identify all the generated cracks. Moreover, propagation of some of the cracks also occurred due to material removal in FIB milling.