Mechanical characteristics of solution grown potassium zinc chloride crystals doped with lithium ions

Results of indentation-induced hardness testing studies on potassium zinc chloride crystals doped with Li⁺ ions, leading to an understanding of their mechanical behaviour, are presented. The Vickers hardness of these crystals for (1 0 0), (0 1 0) and (0 0 1) planes in the load range 20–160 g were studied. Load-independent values of hardness are estimated for the three crystallographic planes by applying Hays-Kendall’s and Li-Bradt models. The results showed that: (1) for the three crystallographic planes the load-independent hardness obtained by Li-Bradt model is higher than that predicted by Hays-Kendall’s, approach; (2) the load independent hardness of the (0 0 1) plane is higher than that of both (1 0 0) and (0 1 0) planes, (3) the values of load-independent hardness depend on Li⁺ concentrations in the K₂ZnCl₄ crystals, (4) the variations of crack length and crack morphology are described for studied crystal planes.