A study on reheating characteristics for thixo die casting process with electromagnetic stirring and extruded aluminum alloys and their mechanical properties

Abstract

In this paper, the reheating process and mechanical properties of thixo die cast A356 alloy, using electromagnetic stirring (EMS) and extrusion before thixo die casting, were discussed. The EMS is used mainly to manufacture raw materials with a globular microstructure. If relevant reheating is carried out, products with excellent mechanical properties can be manufactured by EMS. Contrarily, extruded material has a fine dendrite microstructure and has rarely been assumed to be suitable for the thixo die casting process. This study demonstrated that the microstructure of extruded material could be globularized and applied to the thixo die casting process only with the relevant reheating parameters. This applicability was estimated through image analysis obtaining the solid fraction, the mean equivalent diameter, and roundness under various reheating conditions. After thixo die casting experiments using three materials, which were EMS, low-extrusion material (LER), and high-extrusion ratio materials (HER), mechanical properties were comparatively analyzed. EMS and HER materials show better mechanical properties than LER.