Determination of the elastic constants of oriented polycrystalline Ti 3 SiC 2 via coherent inelastic neutron scattering and ab-initio Molecular Dynamics – Density Functional Theory calculations

Nanolaminates such as the M n+1 AX n (MAX) phases are a class of materials with hexagonal crystal structure for which ab-initio derived elasticity tensors have been published due to sizeable single-crystals not being available. Single crystal elastic constants, however, are fundamental to understanding phase transitions, and a range of mechanical, fracture, wear and electro-mechanical properties. Recent experiments using neutron powder diffraction indicated strong shear stiffness in case of Ti 3 SiC 2 via a large value for c 44 . The data presented in this paper combine neutron spectroscopy and a detailed ab-initio Molecular Dynamics – Density Functional Theory calculation and confirm the magnitude of c 44 without the need of a micromechanical model. Additionally, the calculations allow estimating the remaining c ij using the experimental value of c 44 .