Microhardness studies on nonlinear optical L-alanine single crystals

Abstract

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 (n) 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.

How the H-Bond Layout Determines Mechanical Properties of Crystalline Amino Acid Hydrogen Maleates

“…30 The Young's modulus measurements on some crystal faces have been given, 31 while the measurement by the microhardness method and the calculation of the c 11 component by Wooster's empirical equation have been provided. 32 The latter results seem to be somewhat overestimated, though comparable with other data for β-alanine. 33 The comparison of the experimental and calculated values of Young's modulus on certain crystal faces and the analysis of spatial anisotropy of Young's modulus from the calculated stiffness tensor have been done.…”

“…The experimental microhardness data for different crystal faces have been given, the components of the stiffness tensor have been measured, and the velocities of longitudinal and transverse acoustic waves have also been measured . The Young’s modulus measurements on some crystal faces have been given, while the measurement by the microhardness method and the calculation of the c 11 component by Wooster’s empirical equation have been provided . The latter results seem to be somewhat overestimated, though comparable with other data for β-alanine .…”

Thermal and mechanical properties of La–Al–Sb alloys

“…The sample heat treated at 600°C showed metallic behavior from room temperature to 5 K. The resistivity of the samples heat treated at 800°C increased about 2-12 X cm value that is indicating almost semiconducting type behavior. Considering the XRD results, we believe that the change of the resistivity behavior of the samples is attributed to the changes of the phase formation in the samples with the applied heat treatment conditions [14,[26][27][28].…”

Growth, optical, thermal and mechanical characterization of an organic crystal: Brucinium 5-sulfosalicylate trihydrate

“…Indentation hardness testing is one of the methods used in the microstructural investigation (Zhu and Xuan 2010). Several researchers have studied the importance of hardness of crystals (Subhadra et al 2000;Rao et al 2002;Sangita et al 2005;Hanumantharao and Kalainathan 2013). Measurement of hardness provides useful information about the mechanical * Author for correspondence (anbu24663@yahoo.co.in) properties such as elastic constants (Wooster 1953), yield strength (Westbrook 1958), etc.…”