Structure investigation of the Al-Si-Cu alloy using derivative thermo analysis

Purpose: This research work presents the investigation results of derivative thermoanalysis performed using the UMSA device (Universal Metallurgical Simulator and Analyzer). The material used for investigation was an Al-Si-Cu alloy known as AC-AlSi7Cu3Mg grade aluminium cast alloy. Design/methodology/approach: As a result of this research the cooling rate influence on structure and mechanical properties changes, especially HB Hardness was investigated. The cooling rate was set in a variable range of ~0.2 oC/s to ~1.25 oC/s. In this work structure changes were determined concerning the structure, especially the dendrites and grains and particle distribution in the aluminium matrix. Findings: The reason of this work was to determine the optimal cooling rate values, to achieve good mechanical properties for protection of this aluminium cast alloy from losing their work stability and to make it more resistant to action in hard working conditions. For investigations of the aluminium samples hardness measurements of the different sample areas were performed. The material was examined metallographically and analyzed qualitatively using light and scanning electron microscope as well as the area mapping and point-wise EDS microanalysis. The performed investigation are discussed for the reason of an possible improvement of thermal and structural properties of the alloy. The investigation revealed the formation of aluminium reach (. -Al) dendrites and also the occurrence of the .+ß eutectic, the ternary eutectic .+Al2Cu+ß, as well the occurrence of the Fe and Mn containing phase was confirmed. Practical implications: In the metal casting industry, an improvement of component quality depends mainly on better control over the production parameters. Originality/value: This work provides also a better understanding of the thermal characteristics and processes occurred in the new developed near eutectic Al–Si-Cu alloy. The achieved results can be used for liquid metal processing in science and industry and obtaining of a required alloy microstructure and properties influenced by a proper production conditions.