Cast-Forge Process for Al-Zn-Mg Alloy by Applying Semi Solid Injection to Preform Casting

Abstract

Magnesium has the smallest specific gravity in the structural metallic material applied to automotive parts. It is expected to be suitable light material to meet the needs of a vehicle weight reduction in recent years. However, as magnesium alloy has low forgeability due to its crystal structure, forged magnesium application is quite few in automotive parts. Therefore, if the cast- forge method can be applied for magnesium alloy, it is expected to reduce the process number and improve the yield of the material. In this research, semi solid magnesium injection molding process has been studied as a method to obtain the perform with refined grain size of the crystal which is smaller than that of the method of gravity casting. In addition, the influence of various factors on the mechanical property has been examined. Moreover, this new cast -forge process which was combined with semi solid metal injection and forging was applied for actual automotive part. As a result, it was proved that the preform fabricated by semi solid injection had high forgeability and the studied new process had high potential as manufacturing process applied for actual structural member.