Nano tungsten carbide interactions and mechanical behaviour during sintering: A molecular dynamics study

Abstract

In the present research paper, atomistic simulation at microscopic level has been performed for sintering of nanocrsytalline tungsten carbide particles. The sintering parameters like dihedral angle, neck width, and shrinkage ratio have been evaluated during sintering. The Radial Distribution Function (RDF) and Mean Square Displacement (MSD) for atoms have been simulated in order to understand the crystal structure properties and diffusion behaviour of the atoms. The solid state sintering (heating in range of0.6-0.8Tm) has been performed at two different heating rates i.e. 2.5 K/ps and 4.63 K/ps for various size of particles i.e. (2 – 8 nm). The sintering behaviour for 4 nm size particle has been analysed. It has been found that neck width in case of slower heating rate is 33 Å, which is more than the higher heating rate. Besides this, the maximum dihedral angle of 1120 has been found during sintering which lies in the range of solid state sintering of the nano scale powders. The diffusivity coefficient calculated during various sintering rate has been found to be 5.25×10-14m2/s and 1.05×10-13m2/s. In order to check the tensile properties of sintered particle, uniaxial tensile test simulations have been performed at strain rate of 1010 s−1. The maximum strength of 4235 MPa and 3690 MPa has been achieved by slow and fast heating rate sintered particles respectively. The tensile strength variation with respect to temperature has also been studied during the sintering process. This Molecular Dynamic (MD) study in turn has laid the platform for setting of the optimum parameters during sintering of WC powders at nano scale level.