Desarrollo del proceso tixo forjado lateral para la fabricación de estructuras híbridas acero-aluminio

Abstract

Iron and aluminum alloys are among the most important  materials in automotive industry because of their good  properties. Combining both materials in a hybrid structure will implement the integrated load-supporting of steel with the  advantages of aluminum in weight reduction. However, due  to the highly differing physical and mechanical properties,  metallurgical bonds between these materials are difficult to  achieve with traditional welding methods. These differences  in properties lead to the formation of hard and brittle  intermetallic compounds (IMC) along the transition line which  will significantly decrease the mechanical properties of the  joining area.  Production of hybrid components by thixoformig of aluminum  on steel is a promising method to manufacture near net shape  components with good mechanical properties in a single  process step. This process allows to join dissimilar materials in  semisolid state at lower temperatures than traditional welding  methods, causing a decrease in thickness of the intermetallic  layer. In this work, the mount of the front cradle of the car was  manufactured in A356 aluminum alloy and joined to a S355JH2  quality steel tube in one step by thixo transverse forging  method. In order to determine the quality of the component  and the joint a complete mechanical and a qualitative  metallographic analysis was carried out. The results revealed  that quality hybrid components can be achieved regarding the  intermetallic bond, although geometric redesign is necessary to reduce local stresses.