Water-aluminum reaction by MD simulations and its interpretation defect formation

Abstract

Many of the aluminum and its alloys are produced by casting methods. During casting, aluminum is heated to temperatures above melting point. In the liquid state, aluminum reacts with water vapor to form aluminum oxide on the surface and hydrogen is dissolved in the melt. These are the two most critical defects that deteriorate the properties of the cast part. Therefore, it is important to investigate the possible reactions of water vapor with liquid aluminum in order to understand the formation of these defects. In this work, Molecular Dynamic (MD) analysis was used to evaluate the reactions of water vapor with aluminum at various temperatures (300, 500, 700, 900 and 1100 K). It was found that when aluminum reacts with water vapor, aluminum oxide layers form on the surface of the aluminum block. In addition, mono and di-atomic hydrogen are released due to the reaction between aluminum and water. These free hydrogen atoms are distributed homogeneously and rapidly in the aluminum block and gap between two aluminum blocks.