Influence of process-related oxide formation during shaping of aluminum fiber mats in the mushy state

Conventional semi-solid-methods offer a variety of options concerning the production of parts with appropriate mechanical properties as well as complex geometries. However, they are only partly suitable for the production of large-area thin-walled components. When using a globular pre-material, segregation occurs increasingly with increased deformation. For this reason a novel metallic flexible fiber material, which can be already inserted extensively in the die, is used as feedstock for the first time. After transferring the material into the semi-solid state, it will be shaped by using a simple lifting tool. Due to the shape of the flexible feedstock the danger of introducing additional oxides emerges which may cause a disadvantage for mechanical properties of the finished parts. However, the flexible feedstock provides the opportunity to reduce the degree of deformation as well as the avoidance of segregation by mainly shaping via height. Finally, these fibers can be crimped to a homogeneous structure. During the transferring process into the semi-solid state additional process-related oxides are formed. These oxides on the fiber surfaces create an influence the connection of fibers among themselves. In order to prevent the formation of process-related oxides a protective gas atmosphere can be used, which leads to slight improvements of mechanical properties. Furthermore, additional process steps have to be examined in order to distribute the oxides in the microstructure finely.