Anisotropic elastic recovery behavior of AlN ceramic during nanoindentation and scratching

The anisotropy of the grain orientation of aluminium nitride (AlN) ceramics leads to great differences in elastic recovery of grains which makes it difficult to achieve high machining accuracy. In this study, the anisotropic elastic recovery behavior of AlN ceramic was investigated by nanoindentation and scratch experiments. The results show that as the main Euler angle the grain increases, the elastic recovery rate of the indentation decreases from 39% to 31%, and the elastic recovery of scratch decreases from 47% to 39%. However, there is a local peak in the elastic recovery rate when the main Euler angle is 75° during scratching. Through the analysis of the Schmid factor, it is found that the ease of activating the sliding system of a grain has a great impact on the elastic recovery rate of scratches. Through further analysis, the elastic recovery rate of grains is mainly affected by the combined action of the base slip system and the prismatic slip system during scratching. The prediction models of the elastic recovery rate during nanoindentation and scratching were established and the prediction results are consistent with the experimental results, indicating the reliability of the prediction model.