X-ray computed tomography of cast metal matrix composites

Abstract

The development of new cast metal matrix composites and technological processes for their production are inextricably linked with the need to improve the methods of quantitative non-destructive testing. In this work, the features of the spatial structure of cast in-situ metal matrix composites (on example of the Al – Mg2Si system) were studied using X-ray computed microtomography. The parameters of tomographic scanning were optimized to identify structural components with close ranges of radioparency. The rational selection of the scanning parameters of the samples made it possible, during the subsequent computer processing of the slice sets, to clearly identify the structural constituents of the metal matrix composites depending on the gray levels in their comparison with the characteristic morphology of the observed constituents (primary Mg2Si crystals, pseudobinary eutectic, compounds of impurity elements). The total volume of porosity in the studied samples of Al + 15 wt.% Mg2Si composites after melt thermal-rate treatment at 900 °C did not exceed 0.05 mm3, which corresponds to a porosity content in the sample of 0.13 vol.%. The presented results show the significant potential of tomography in the study of the structural and morphological characteristics of composite materials and internal defects in cast products made from them. This research was funded by the Russian Science Foundation (Project № 20-19-00687).