Metalografická analýza defektů v AlSi7Mg odlitcích detekovaných při NDT kontrole

Abstract

The goal of this diploma’s thesis is to analyse and describe the internal defect in hypoeutectic silumin brake caliper casting. Defect is known to be cavity shrinkage detected at X-Ray inspection in standard process flow. Research part of the thesis is focused on characterization of hypoeutectic aluminium alloys, methods of different NDT inspection designed for metals and techniques of structure characterization used to investigate internal defects. In experimental part of the thesis, production batch information, chemical composition of received samples and brief introduction to used casting technology were presented. Samples for metallographic analysis using were prepared by cutting, grinding, and polishing. Light microscopy was performed on polished samples to characterize the defects and their surroundings. Additional analysis is performed on scanning electron microscope with EDX to determine local chemical composition. In future, findings will be processed into proposition of possible corrective actions to ensure elimination of the defect during the casting process.