Why is so hard to grow a perfect crystal? - 2D and 3D Monte Carlo simulations

TL;DR

This paper uses Monte Carlo simulations to explore the complexities of crystal growth, revealing phenomena like crystallization shrinkage, stress accumulation, and porosity formation that impact material properties.

Contribution

It demonstrates that crystallization continues within grains after shrinkage stops, leading to porosity due to stress accumulation, using both experimental data and simulations.

Findings

Crystallization shrinkage halts at the percolation threshold.

Crystallization-induced porosity forms due to stress accumulation.

Simple potentials like Lennard-Jones can model complex crystallization phenomena.

Abstract

We focus our attention on Monte Carlo simulations of crystallization, which is one of the most important processes occurring in nature and technology of materials. Special attention is paid to the crystallization shrinkage and its consequences onto the growth of the new crystalline phase. We show that crystallization shrinkage stops after reaching the percolation threshold and that this is not the final stage of the crystallization process. Based on experimental evidences on sintering of diopside-albite systems and computer simulations we argue that crystallization continues inside the grains where the remaining liquid melt is a subject of accumulation of stress and because the stress relaxation by change in the volume is forbidden due to the already formed rigid core, the so called crystallization induced porosity appears. We show that even a relatively simple short range potential as the Lennard-Jones one, reveals such a complicated phenomenon as the crystallization induced porosity, which has a great importance onto the mechanical properties of the newly crystallized material.