Three-dimensional reconstruction of bifilm defects

Abstract

Bifilm defects have been proposed to be critical for the generation of various metallurgical defects in castings and have been reported to exist in various composition-based alloys. However, the geometry structure of bifilm defects has not yet been well understood. This present work reconstructed the bifilm defects in a nickel-aluminium bronze alloy casting in three-dimensional (3D) space through the use of computer tomography technology. It was shown that the shape of the bifilm defects is very complex and different from a spherical defect in 3D space. The bifilm defects were experimentally extracted successfully by an electrolysis method and were imaged, which confirmed the folded double-layer structure of the bifilm defects. These results will shed new light on the understanding of bifilm defects and improve the defect control engineering of castings.