Microhardness studies on nonlinear optical L-alanine single crystals

摘要

Vickers and Knoop microhardness tests were carried out on grown L-alanine single crystals by slow evaporation technique over a load range of 10-50 g on selected broad (2 0 3) plane. Vickers (H_v) and Knoop (H_k) microhardness for the above loads were found to be in the range of 60-71 kg/mm~2 and 35-47 kg/mm~2, respectively. Vickers microhardness number (H_v) and Knoop microhardness number (H_k) were found to increase with increasing load. Meyer's index number in) calculated from H_v shows that the material belongs to the soft material category. Using Wooster's empirical relation, the elastic stiffness constant (c_(11)) was calculated from Vickers hardness values. Young's modulus was calculated using Knoop hardness values. Hardness anisotropy has been observed in accordance with the orientation of the crystal.