Mechanisms of the nanoscopic deformation of SiC and KDP

With the rapid advances in a wide range of scientific and technological fields such as those in electronic, biomedical, optical and aerospace engineering, deep insights on the nanoscopic deformation mechanisms of advanced materials have become more and more important. Silicon carbide (SiC) and potassium dihydrogen phosphate (KDP) crystals are typical examples. Compared with experiments and continuum-based modelling methods such as the finite element method, molecular dynamics (MD) analysis is a nanoscopic method to numerically simulate the physical movements of atoms in a material and thereby to understand the microstructural changes in the material under external loading. The deformation details can be as the dynamic process of dislocations and phase transformations. This chapter will provide a comprehensive review on the investigations into the nanoscopic deformation mechanisms of SiC and KDP using MD simulations under various mechanical loading conditions. First, the basic procedure of MD simulations on a mechanical deformation system will be briefly introduced, including selection of potential functions for these two kinds of materials. The discussion will then concentrate on the major influential factors to the simulation reliability, such as the effects of temperature, anisotropy, phase transformation and dislocation evolution. Specific loading conditions, such as uniaxial tension and compression, nanoindentation, nanocutting and nanocutting, will be used as the primary mechanical deformation models for the discussion.