Thixoforging of Ultrasound Treated 6060 Aluminum alloy

In the last years researches on thixotropic materials have been developed in order to introduce this new technology in manufacturing processes. Considering high pressure die-casting, several applications are present in literature mainly related with low melting point alloys (Al and Mg) because of the limited die life experienced when casting higher melting materials. In the case of conventional forging, semi-solid processing needs higher performance materials and/or coatings for the mould because of the working temperatures; however, the advantages of obtaining near net shape part in a single step, with reduced machining and finishing costs are evident. These returns, combined with the lower required forces that reduce the mechanical wear, make the semi-solid forging technology competitive.
The present paper deals with the thixoforging of aluminum 6060 alloy, whose semi-solid microstructure was obtained by ultrasound treatment. The aim of the research was to investigate the influence of process parameters on the final forged part quality. Different pre-heating billets temperatures, corresponding to different liquid fractions, were used and the needed forging forces were monitored by using load cells and compared to that obtained during drop forging. A metallurgical analysis of the forged parts was also performed in order to evaluate their quality and properties.