Investigations on indentation induced hardness and fracture mechanism in flux grown DyAlO3 crystals

Results of Vickers' microhardness (H-v), fracture toughness (K-c), brittleness index (B-i) of (110) and (001) faces of flux grown dysprosium aluminate crystals, in the load range of 10-100 g are given. The variation of microhardness with load is found to be non-linear and is explained by using Hays and Kendall's law. Applicability of Hays and Kendall's law gives us the load independent values of hardness. Hardness anisotropies for both the crystal planes are reported. The cracks are classified into Palmqvist and Median types. There is a transition from Palmqvist to Median types of cracks at higher loads. The values of fracture toughness (K-c), brittleness index (B-i) and yield strength (sigma(y)) are calculated using median type of cracks. (C) 1998 Elsevier Science B.V. All rights reserved.