3D study of the structure of primary crystals in a rheocast Al-Cu alloy

Abstract

An Al-10.25 wt.% Cu alloy was mechanically stirred at 1000 rpm while being cooled to and isothermally held at 619°C for various times before casting. The microstructure of as-cast materials consists of pseudo-particles and pseudo-clusters in two-dimensional (2D) views. Serial sectioning was performed and it was found that pseudo-particles belonging to a pseudo-cluster were connected in three dimensions and a pseudo-cluster was actually a single primary particle. A three dimensional (3-D) model of such a primary particle was constructed from 2D sections which showed the complexity of its structure. It is suggested that the theories based on agglomeration and disagglomeration of particles duri..